I think we would all save a lot of time and avoid a lot of stress if it was the standard thing to do to declare at the start of a piece of writing how much of it was written by hand, and how much with or by AI and in what sense (i.e. was it fully vibe-written or just proofread to correct grammar etc).
I mean I really, really wish people did that. I don't want to fulminate since it's against the guidelines but presenting a piece of text that you haven't written entirely yourself and claiming its authorship as entirely your own is the definition of plagiarism. I think that's what bothers me the most. If you use AI and it contributes to the content of your text at all, why not just let us know? It's the fair thing to do. Don't make it look like you wrote something, or wrote it entirely on your own, when you haven't.
I think that would suffice to cool down the debate quite a bit, because then we wouldn't be constantly trying to double-think each other all the time. We'd be free to concentrate on the merits and demerits of a piece of writing for its own worth.
Not saying I, for one, wouldn't still be prejudiced, but if AI writing really gets better than human writing there will come a time that even hard-headed curmudgeons like me will have to admit it. Or just go and fume alone in the corner.
This is certainly not the case now and since almost nobody ever says "this was written with/by AI" we end up in the kind of double-guessing spiral we're in here.