Because they’re rational enough to realise they have exactly zero chance of achieving that goal, perhaps?

The way they get instantly dismissed, laughed at, or funny looks if they suggest a ban on meat would tend to discourage, if not such a goal, then at least mentioning it.

(Achieving it by admitting that’s their goal, at any rate - I suppose they could sneakily have that goal and have a “moral softening-up” agenda already.)

Aren’t rational choice assumptions perfectly consistent with these solutions given preferences for being moral?

Are you ONLY making the descriptive claim? Because what you say in the third paragraph - that “if we’re talking about whether or not a certain constraint on self-interest ought [your emphasis] to be normatively binding … I think there’s a good answer to that: because heeding the constraint will tend to make the person who heeds it better off, conditional on others heeding it, too” - sure seems to have a normative dimension as well. (Or am I missing something?)

Are you coming out as a rule utilitarian?

The debate is always if the people are actually coming first. Sometimes we put air before people. That is immoral.

Leaving that aside, it seems to me that it might be helpful to bring into consideration how conditionality can be related to rational ignorance on moral issues. Rational ignorance comes into the equation because it takes effort for me, and people like me, to work out a moral position from scratch, particularly on complex issues like climate change. So a lot of us tend to follow the lead of preachers of one kind or another (including the secular variety). But we don’t just follow blindly - our willingness to follow is often conditional on the preacher’s actions. We expect the preacher to “put his or her money where his or her mouth is” i.e. to set an example through his or her own behaviour. And we tend to stop following when a preacher doesn’t practice what he/she preaches.

Yes.