This is not always the case, but I get the impression that many of them are paid shills, astroturf accounts, bots, etc. Including on HN. Big AI is running on an absurd amount of capital and they're definitely using that capital to keep the hype cycle going as long as possible while they figure out how to turn a profit (or find an exit, if you're cynical - which I am).
Not really. I'd rather find out very quickly that someone doesn't know a domain space rather than having to wade through plausible looking but bad answers to figure out the exact same thing.
At this point it's foolish to assume otherwise. Applies to also places like reddit and X, there are intelligence services and companies with armies of bot accounts. Modern LLM makes it so easy to create content that looks real enough. Manufacturing consent is very easy now.
