I don't know if the tide has shifted on this site, but I was scolded by dang some months ago for pointing out something was obviously GPT-written. I guess that's against the rules.
Out of curiosity, where was that? The only moderation reply I can find to you is https://news.ycombinator.com/item?id=43797043.
There's a rule against commenting about "tangential annoyances" like text formatting or bad UX on a linked website. It's possible a comment about GPT use might have been interpreted as that, but I would disagree - this has an effect on the quality of the content. Either way this rule is not very consistently enforced as far as I observed.