People also forget to distinguish principled-morality-in-perfect-company vs principled-morality-when-surrounded-by-limited-entities. In fact, every "principled" analysis (and note that i object to the term - real-world is messier and more complex, but not unprincipled) is actually a modeling choice of what things to assume away. It's never "morality about a point-mass", it's about choices within some constraints.
Principled vs. pragmatic morality is definitely closer to a spectrum than a dichotomy.
"It's never "morality about a point-mass", it's about choices within some constraints" - Is it? Some people do make moral claims like, "Murder is unconditionally wrong". Perhaps I don't understand what you are saying clearly.
"Murder is unconditionally wrong" puts the human choices under constraints into the definition of murder (or lack thereof - often they mean "killing that I object to"). There's not much value in the abstraction, as all the details come back when you dig in.
One reason why conversations about morality are often unproductive is that there are two seperate conversations that often get mixed together. The first is principled morality: How ought perfect, incorruptible beings with no false beliefs act, further assuming the absence of any side-effects? The second is practical morality: How ought flawed, corruptible beings with false beliefs act, accounting for the possibility of side-effects?
I believe that both of these questions are ultimately valuable: the pragmatic because it tells us how to ultimately act; the principled because it is instructive. This post will focus on defending the value of discussing principled morality as people on Less Wrong generally don't object to discussing pragmatic morality. However, I grant that there might exist some very strong deontologists who would require the opposite message. More commonly though, I suspect that people who ignore pragmatic morality have just accidentally skipped a step and forgotten to account for practical considerations.
I already explained in my post on the Direct Application Fallacy that even if a hypothetical situation never occurs in real life, it can still provide opportunities for learning, be tied back to the real through further argument or make us aware of the limitations of our model. Eliezer expresses a similar sentiment in a recent Facebook post, where he identifies a particular kind of argument as stemming from, "one of those awful durable forms of misunderstanding where Msr. Toolbox doesn't see what you could possibly be telling somebody to do with a "good" or "ideal" algorithm besides executing that algorithm."
Further, separating the discussion of principled and pragmatic issues is important for the same reason that local validity is important. If you have to clearly specify your stance on principled morality and then your stance on how these considerations play out practically, you have less scope to fudge that if you refuse to seperate them.
Objections
Undoubtedly, contextualisers would object that insisting on this kind of discussion is often harmful. For example, someone might oppose torture because they believe that giving a government that much power is too risky. They might want to refuse to discuss the principled question where this consideration is excluded because they might be worried that someone could take their in principle exception and use it to support the policy in practise. However, even though we have to be conscious of the effects of our words in a public settings, if we are to have any hope of coming to the truth, we'll need contexts in which the decoupling-style of conversation is allowed to take place.
Another objection would be that only deontologists need a concept of principled morality, utilitarians don't need them. My response is that I include utilitarianism as a form of principled morality. I would also note that there are different forms of utilitarianism: hedonic/preference, total/sum, act/rule, ect. Plus there are different possible utility functions. If you've already agreed on the precise rule set in advance, then I'm perfectly fine with you skipping the principled discussion.
Another objection would be that these questions are ultimately unanswerable, so we should focus on pragmatic morality instead. I'm not going to insist on a precise model of morality, but you should have at least some idea of what kinds of things you value. Otherwise, there is no reason to think this heuristic has any value. If you say, "Utility, but also freedom and fairness", then that's a starting point. Even if we can't figure out exactly how they relate, we should be able to at least rule some theories out, such as theories that purely optimise for fairness, even if that results in everyone being miserable. I don't have an issue with proposing heuristics if you think universal rules are too hard, but you should at least have some idea of what factors that heuristic is trying to balance and over what range it is reasonable.
Pragmatic Factors
Given all of this, it seems natural to ask what specific factors are relevant in practical morality, but can be ignored in principled morality. Here is a list of some factors we might want to take into account:
I've often seen naive utilitarian analyses which have missed one of these factors when it would make a large difference in what we ought to do. Further, it is worth noting that principled discussion of morality doesn't always exclude all of these factors. Indeed, some of these may sometimes be written into the scenario being discussed. Instead, the focus is on limiting the discussion narrowly, in the hope that this makes progress easier.