https://astralcodexten.substack.com/p/highlights-from-the-comments-on-self 1: Rosemary (writes Parallel Republic) says:

I think a preference for the status quo has to weigh in to some extent.

All else being equal, sure, I agree with the "any group large enough that it isn't ludicrous on its face has a right to self-determination" standard.

But all else is almost never equal. Someone wants to secede and someone else wants to conquer—and all of that is enormously disruptive to many other someones.

So I think there's an immediately obvious utilitarian bias towards the status quo of, oh, the last decade or so. Governments are heavy, complicated things, and I think a group who wants to disrupt that needs to make an affirmative argument based on something other than "self determination" that this is a good idea and all the disruption is worth it for the sake of things being better in the long run.

Which unfortunately gets us nowhere because it brings us right back to debates about culture and history etc.