There's no getting around work (and whatever evidence we have of its proof). When we feel like someone has put a lot of effort into something, we feel they are being genuine and I find myself far more willing to engage with them.
When somebody posts a chunk of text produced by an llm I feel like they didn't put any effort into it and I'm less willing to engage/zap.
(Maybe you can say that the creators of the llm put a lot of work into creating the tech or training it, but in most cases I think we are seeing posts by people who didn't personally do those things and haven't invested very much work in the words they are posting.)
Now, it can be hard to tell the difference, and I suppose that's where the problem is.
My rule is if it makes me think llm, even just a little, it probably is. I might finish the post, but in my mind they've got a strike. Three strikes and I am pretty unlikely to look at posts by that user.
As a side note, I'm not so worried about the veracity/accuracy of a post. I'm very willing to forgive some inaccuracies in a post that feels genuine than makes me think, than I am to feel good about someone who copies a very accurate article from somewhere else and posts it as their own.