I think people are just presuming that others are regurgitating AI pablum regardless.
People are seeing AI / LLMs everywhere — swinging at ghosts — and declaring that everyone are bots that are recycling LLM output. While the "this is what AI says..." posts are obnoxious (and a parallel to the equally boorish lmgtfy nonsense), not far behind are the endless "this sounds like AI" type cynical jeering. People need to display how world-weary and jaded they are, expressing their malcontent with the rise of AI.
And yes, I used an em dash above. I've always been a heavy user of the punctuation (being a scattered-brain with lots of parenthetical asides and little ability to self-edit) but suddenly now it makes my comments bot-like and AI-suspect.
I've been downvoted before for making this obvious, painfully true observation, but HNers, and people in general, are much less capable at sniffing out AI content than they think they are. Everyone has confirmation-biased themselves into thinking they've got a unique gift, when really they are no better than rolling dice.
Thing is, the comments that sound "AI" generated but aren't have about as much value as the ones that really are.
Tbh the comments in the topic shouldn't be completely banned. As someone else said, they have a place for example when comparing LLM output or various prompts giving different hallucinations.
But most of them are just reputation chasing by posting a summary of something that is usually below the level of HN discussion.