Morality isn't generally something we think of as a matter of personal preference.
Upthread I proposed that personal preferences were founded on differences in sensitivities or tolerances. For example, if I am insensitive to the difference in flavour and texture between apples and pears I am unlikely to prefer one or the other (or at least, it becomes very unclear what my grounds for that is so long as I sincerely don't discern any difference between them.)
Not only do we generally think of people as having different levels of sensitivity to moral subjects, we also think of them as having different lists of subjects of morality. For example, for me it might not be a moral matter to invoke a deity's name in cussing, but to someone else it might be.
If you believe something is immoral, then you believe people doing that thing are behaving immorally and should change their behaviour -- you are casting judgement.
I see your point in respect of the normative applications of morality; although that was not my intent and no one replied to me expressing a feeling of judgement as an objection. (That's not to say it didn't motivate their replies.) Posters generally framed their objections around not seeing any risk of exporting immorality from the game.
I wrote upthread that I believed play had a separateness from real life, so that behaviour that could seem immoral in real life might not do so in play. However, I did caveat that by saying that this likely relies on some consciousness and perhaps intentionality about that separateness. The article I linked above about DitV explores this sort of thing.
This separateness applies to moral judgement: I can hold mass slaughter to be immoral in the real world and judge those who are indifferent to or promote it
without applying the same judgement to play. And this is on the same grounds others have raised for separating immoral action in fiction from real life. (Meaning that if it is mistaken, they too are mistaken.)
If you present something as just a matter of personal preference, then it is assumed you are not ascribing moral or ethical value to the behaviour.
Why should that be true in the context of pretences we entertain as part of playing a game? Suppose I believe that in the real world it is immoral to X, and I prefer in game not to entertain X. Another player feels better able to uphold a separateness between game and real world, so even though they agree it is immoral to X, they are willing to entertain it in their play. Those sorts of differences are part of what motivates safety tools now incorporated into many TTRPGs.
To put it plainly, if you believe that there is a separateness between play and our real world, so that doing X which would be immoral in our real world is not immoral in play, then desiring not to do X in play can indeed be a matter of personal preference.
Edit: Of course it is OK to have concerns on moral grounds, but don't expect people to simply accept suggestions that their gaming preferences might be immoral without a very convincing argument.
I think someone could say that it is indeed immoral to entertain mass slaughter in the real world, but not immoral to do so in game play, due to the separateness or magic circle of play. I imagine, but am perhaps mistaken, that there are moral subjects most folk here would feel compunction about incorporating in their play.
@AlViking disfavours minion mechanics on grounds that matter to them, and they have said that they do not impose that on others. I can disfavour minion mechanics on other grounds without imposing that on others. There is nothing untoward about either of us explaining our grounds just in case others find on reflection they share them.
