Upvoted for being a good & concise distillation of your concerns.
(2) I think monogamy can be justified rationally, but this involves reconstructing certain values that have been eclipsed by consumerist logic
Which values would these be, and what do you mean by reconstructing them? I'm listening.
(3) The demand to justify our sexual practices or risk being put into stigmatized position of conformist is unfair.
Well, as someone said to you above, I don't think WrongBot's intention was to stigmatize anyone. You could have simply said "I personally find polyamory icky" and that would have been considered a perfectly valid 'justification.' I understood him to be saying merely: here is an opportunity to reflect on this norm - I personally found my rejection of it to be a net positive in my life.
There's a stronger claim lurking here, that many people consider maximum choice and flexibility the royal road to happiness and since polyamory more adequately embodies this ideal, it is superior to monogamy, at least for those people.
This is, IMO, your most interesting and defensible claim. It is certainly plausible that some or many modern Westerners and polyamorists are fetishizing "variety of choice" in their decisions, in the naive belief that greater choice leads to greater happiness. However, what is the right way of making such decisions then?
Once people examine their beliefs in the cold light of reason, they will choose what works for them, etc.
I suspect you're defining "reason" too narrowly. For me, the 'reasonable decision' is basically by definition the best decision, given a thorough weighing of all potential factors that could come into play - including whatever objections to polyamory and arguments for monogamy you might have! Moreover, reason's light is not cold, since before it can even get off the ground, it needs to know our warm and fluffy terminal values. When you think of reason, think "All Things Considered," don't think "Spock."
I'll repeat something I alluded to before: a happily married woman who listens to her sister's dramatic dating stories and feels relief that she no longer has to worry about all that. This is an example of how removing choice and flexibility can be the source of happiness. This requires us to see choice in negative terms, which is actually quite difficult to do, because the problems of a lack of choice have been dramatized in movies and novels so often that we have a strong emotional resonance with them - for example, the familiar narrative of the son who ...
Many of us are familiar with Donald Rumsfeld's famous (and surprisingly useful) taxonomy of knowledge:
But this taxonomy (as originally described) omits an important fourth category: unknown knowns, the things we don't know that we know. This category encompasses the knowledge of many of our own personal beliefs, what I call unquestioned defaults. For example, most modern Americans possess the unquestioned default belief that they have some moral responsibility for their own freely-chosen actions. In the twelfth century, most Europeans possessed the unquestioned default belief that the Christian god existed. And so on. These unknown knowns are largely the products of a particular culture; they require homogeneity of belief to remain unknown.
By definition, we are each completely ignorant of our own unknown knowns. So even when our culture gives us a fairly accurate map of the territory, we'll never notice the Mercator projection's effect. Unless it's pointed out to us or we find contradictory evidence, that is. A single observation can be all it takes, if you're paying attention and asking questions. The answers might not change your mind, but you'll still come out of the process with more knowledge than you went in with.
When I was eighteen I went on a date with a girl I'll call Emma, who conscientiously informed me that she already had two boyfriends: she was, she said, polyamorous. I had previously had some vague awareness that there had been a free love movement in the sixties that encouraged "alternative lifestyles", but that awareness was not a sufficient motivation for me to challenge my default belief that romantic relationships could only be conducted one at a time. Acknowledging default settings is not easy.
The chance to date a pretty girl, though, can be sufficient motivation for a great many things (as is also the case with pretty boys). It was certainly a good enough reason to ask myself, "Self, what's so great about this monogamy thing?"
I couldn't come up with any particularly compelling answers, so I called Emma up and we planned a second date.
Since that fateful day, I've been involved in both polyamorous and monogamous relationships, and I've become quite confident that I am happier, more fulfilled, and a better romantic partner when I am polyamorous. This holds even when I'm dating only one person; polyamorous relationships have a kind of freedom to them that is impossible to obtain any other way, as well as a set of similarly unique responsibilities.
In this discussion I am targeting monogamy because its discovery has had an effect on my life that is orders of magnitude greater than that of any other previously-unknown known. Others I've spoken with have had similar experiences. If you haven't had it before, you now have the same opportunity that I lucked into several years ago, if you choose to exploit it.
This, then, is your exercise: spend five minutes thinking about why your choice of monogamy is preferable to all of the other inhabitants of relationship-style-space, for you. Other options that have been explored and documented include:
These types of polyamory cover many of the available options, but there are others; some are as yet unknown. Some relationship styles are better than others, subject to your ethics, history, and personality. I suspect that monogamy is genuinely the best option for many people, perhaps even most. But it's impossible for you to know that until you know that you have a choice.
If you have a particularly compelling argument for or against a particular relationship style, please share it. But if romantic jealousy is your deciding factor in favor of monogamy, you may want to hold off on forming a belief that will be hard to change; my next post will be about techniques for managing and reducing romantic jealousy.