Or, bear with me there, maybe things aren't so far downhill yet, these users just learned how English is supposed to sound, from the same place where the LLMs learned how English is supposed to sound! Which is just the Internet.
AI hype is already ridiculous; the whole "are you using an AI to write your posts for you" paranoia is even more absurd. So what if they are? Then they'd just be stupid, futile thoughts leading exactly nowhere. Just like most non-AI-generated thoughts, except perhaps the one which leads to the fridge.