Intruiging question - this reminds me of the very thought-provoking essay by Sarah Constanin defending individualism. I am not entirely sure what you mean by 'steelman consumerism' as it could refer to defending the concept's usefulness or defending a more object-level claim about the harmfulness of over-consumption or certain types of consumption (or it could mean something I have not thought of)? I'll try to address the first two briefly to the best of my ability.

As a descriptive concept, 'consumerism' serves a useful historical function in describing a change in the way people engaged in their consumptive habits around the 18th century. I think the core essence of this change is in two parts: (I) the scale of consumption and character of the things consumed; (1I) the relationship of identity to material consumer goods. The first relates to the undeniable fact that in some parts of the world, (eg, the developed west), a large proportion of the population has been able to engage in luxury spending. That is, buying things which do not contribute to basic living functions. Afaik, scholars do not suggest this is a change in human nature, but an observation that material plenty has enabled greater spending on luxury goods. In turn, this has led to consumption taking on a greater role in the economy and in the culture of society (eg, shopping mall becoming a centre of community planning). This leads to (II). Historians also suggest that around the 18th century to 'consume' took on a different role. Instead of being seen primarily in a negative light (eg, to extinguish, and as a part of the deadly sins), it took on a positive connotation of productivity and creativity. It became socially acceptable - and even advantageous - for large portions of the population to pursue consumption openly (conspicuous consumption) and with no other justification than fulfilling desires. In turn, this has led to a culture where consumption is encouraged in all parts of life; there are few moral limits on what you spend your money on; and people increasingly identify themselves, and their status, with their consumptive purchases. This is substantially different from the pre-18th century environment of highly moralised and restrictive consumption. Whether you think (I) and (II) are true - and potentially interesting - will shape your view on the usefulness of 'consumerism' as a general concept.  

In terms of the object-level criticism of 'consumerism', several (not necessarily compatible) arguments can be made. Note that many of these involve positing a kind of lexical ordering of goods/life-pursuits which you may disagree with, and hence will find unpersuasive. 

• Although 'consuming' is not itself bad, one should try as hard as possible to avoid relying, fixating, or focusing on material goods. This is to pursue 'higher-order' ends like spirituality and personal virtues which a focus on material consumption can distract from. Represented historically by stoics, buddhists, and many other varieties of religious ascetics. 
• A kind of secular version of the argument above suggesting that 'the most important things in life' (family, friendship, personal virtues, adventure, spontaneity, etc) can be (A) acheived with little - though not a total absence of - material goods; and (B) often focusing on consuming above this threshold brings tradeoffs with these lexically superior things. For example, getting stuck in a 'lifestyle trap' to sustain a high level of consumption (two cars, big house w/ high mortage, private school for kids), but as a result doing an evil/boring job and 'wasting' your life. How do we determine these important things? One example is to look at deathbed regrets - most people don't regret seeing their kids' birthdays instead of working overtime to fund a bigger car. This theme is repeated in a variety of movies and literature - writers seem to believe that accruing large quantities of material goods is not a satisfying narrative payout (comapred to say, love or 'the friends we made along the way')
  • Obviously there are counterarguments such as (1) Why prioritise deathbed you over current you? What gives them epistemic priority? and (2) who are you to tell me 'I am wasting my life!', and who chooses what is important? Further, it may be some people are genuinely fulfilled by buying large quantities of material goods. 
  • A response could be that (I) people often regret their lives in the moment, and consumerism has a way of trapping people in irrational - at least, according perhaps to a counterfactual version of themselves living a more fulfilling life - life paths; (2) There is no satisfying theoretical response to this. Parfit raises this problem with his 'muzak and potatoes' argument - that no quantity of pleasure from those items could outweigh the pleasure of Mozart's music. That said, it may be that the proportion of those trapped, according to (I), is actually quite high (either because of consciously experienced lifestyle traps or a lack of awareness/access of/to other lifestyles). The problem then of consumption culture is that it misleads people into not fulfilling some idealised rational version of themselves's values. 
• A creative argument (seen from the traditional right and the far left) that consumerist culture, defined above, makes it harder to produce great art/culture. The idea is that an excessive focus on mass-consumption, and profits from this, drives artists to make content for the lowest common denominator, and thus they no longer make 'transcendent' or 'great' art. This is where the term 'selling out' comes from, which is inextricable tied to consumerism. Naturally it also relates to how one assesses 'great' art (is there such a thing? There is at least new and innovative art which consumerism might hamper). 
• I should also note that many of these arguments also hinge on how one consumes. The wine-taster, for example, is apparently more morally appealing than the inveterate day-drinker. Similarly, their approach to comfort and convenience is complex. The more extreme view is that both these factors are effectively unnecessary for a good life (especially common amongst religions), and in fact distracting. The more moderate view is that they are valuable, but comfort and convenience above a certain point are (I) overrated, insofar as you get stuck on a hedonic treadmill, and (II) can prevent you experiencing other, valuable states (eg, going 'out of your comfort zone'). 

These are a few arguments, I've tried to focus on the ones I find most persuasive. Although I would like to reduce many of these to empirically testable propositions, I fear, in fact, the crux of the debate may hinge on how 'elitest' you are willing to be about ways of leading a fulfilling life. 

(There are also political arguments along the lines of 'it is bad for the environment', or 'it prevents a worker revolution by instilling fascination for trinkets etc', but I feel they do not get to the heart of consumerism insofar as they are defined by their consequences, rather than the intrinsic ills of consuming as a primary end.)

Ideally, an open public debate on (A) the extent to which we allow money to determine the strength of voices in a community, and that advertising is one of these voices with as much cultural and political baggage as, say, a local political party; (B) adverts are becoming increasingly effective using micro-targeting, and will only become more so; and thus (C) we need to consider more limits on where and when adverts can be shown. 

Pragmatically, more restrictions on online adverts and adverts in public spaces would be a start, in terms of size, spending, and possibly developing categories of adverts depending on their source (multinational versus local business). Perhaps certain areas could be zoned to allow greater advertising, such as shopping districts, where the individuals in them likely want to see adverts. Overall, a greater ability to 'opt-in' to advertising should a person want to. 

The counterargument that this would decrease consumption on the basis people would not know what there is to buy is probably true and a real tradeoff. Without advertising we lose the opportunity to stimulate consumer desires beyond what they would be otherwise, slowing down the market. 

Interesting point. One counterpoint is that most criticisms of 'beauty standards being enforced' reference beauty products or other products sold with the implicit promise they will make you beautiful. Eg, leeching off our shared notion of beauty by linking it with a dieting product. 

But something more complicated definitely seems to be going on here. We have a constructed notion of beauty ('model-thinness') being used to sell random products, such as Ibuprofen. It is almost as if one advertiser is leeching off the other's constructed notion of beauty (Hyperreality?) 

The criticism of 'enforcing beauty standards' in an ibuprofun case may flow from this double falsehood: the advertising target might see thin models in a swimwear advert and thinks 'so the advert is trying to tell me that I should buy this bikini because beautiful people wear it, and that thin model is supposedly beautiful. I don't think she is, but others might, and the fact they use the association suggest a lot of people do, so I should play along' 

That would follow from the other model of advert operation mentioned in one of the footnotes: promising others might buy into the advert, even if you don't. 

This is a little provisional - do you think this is what's going on, or could there be more going on I've missed?

Thanks for the comments - you're right on the first point, I didn't want to go into too much detail on the regulation of adverts because it raises many political and philosophical issues. 

The freedom of advertising is almost certainly a facet of the liberal state. Certain counter-examples stick out, such as limits on tobacco advertising, fast food advertising, and advertising aimed at children. The former two seem premised, at least in the UK, on a notion the wider public is burdened by the consumption of these products, and possibly on the basis we can all agree on health as an unqualified good. The latter is an instance of the advert target being regarded as too susceptible to manipulation. Whether these are plausible or sustainable exceptions is a wider question. 

On the second point, my point was a little opaque. Even if we individually reduce consumption of adverts, and notice how they affect our beliefs, that doesn't change the fact we must interact with others who consume adverts unquestioningly. Further, these interactions will involve the use of shared concepts, which can be altered and undermined regardless of the vigilance of specific individuals. So, in terms of action we could attempt to inform others of the harms of advertising and convince them to be more critical; likewise, we could associate with others who share our view on advertising and work together in this educational project. Within these groups, we would also be able to communicate and spend time together without as much influence from the effects of adverts. 

The emphasis should probably have been on the second part of the sentence - that this is a collective issue so will require some form of collective action if we wish to change the broader cultural landscape. 

Great post, thanks! Widespread value pluralism a la 'well that's just, like, your opinion man' is now a feature of modern life.  Here are a pair of responses from political philosophy which may be of some interest 

(1) Rawls/Thin Liberal Approach. Whilst we may not be able to agree on what 'the good life' is, we can at least agree on a basic system which ensures all participants can pursue their own idea of the good life.  So,(1) Protect a list of political liberties and freedoms and (2) degree of economic levelling. Beyond that, it is up to the individual what concept of the good they pursue. Scott Alexander's Archipelago is arguably a version of this theory, albeit with a plurality of communities rather than a single state. Note it is 'thin' but not nonexistent - obviously certain concepts of the good, such as 'killing/enslaving everyone for my God', are incompatible and excluded. 

(2) Nussbaum 'Capacity' Approach. Bit like Liberal+ approach. You take the liberal approach then beef it up by adding some more requirements: you need to protect the capacity of people to achieve wellbeing. Basically - protect life, environment, health/bodily integrity, education (scientific & creative), practical reason, being able to play, hold property, form emotional and social attachments. The main difference with (2) is that it is a thicker conception of the 'good life' - it will deny various traditional forms of life on the basis they do not educate their children or give them critical thinking skills. Hence, Nussbaum champions the notion of 'universal values.'

Going from (1) to (2) depends on how comfortable you are with an objective notion of flourishing. IMO it's not totally implausible given commonalities across cultures of values (which Nussbaum points out - moral relativism is often exaggerated) and various aspects of human experience. 

If I understand right, your first point is that it makes sense for officials to follow the law because parliament and the courts are better placed to alter it.  Another point is then that it makes sense to limit your activity for the benefit of the group ('individual placing themselves above the group')

These are fairly sensible reasons to obey the law. Does that mean law loses its force when parliament and courts are sufficiently incompetent or crooked? Likewise when acting for a small minority rather than the group? 

Not sure officials think of law this way. Further, an open question whether a system could function with this kind of clause being widely accepted by lawyers and legal officials. 

Great post! I wonder if the 'weirdness' be partially due to intuitions about human freedom of choice. For instance, it seems nonsensical to ask whether unicellular organisms could alter their behaviour to modify models predicting said behaviour, and thus 'control' their fate. Are humans in the same boat?