Do some people have a way of determining when a post is a bot?

I've noticed a lot of threads where many of the responses indicate that people think it's a bot that posted it. Yet, I look at some of these posts, and there doesn't appear to be anything obvious that jumps out that "this is a bot," or at least, maybe I'm not quite sure what to look for.

I mean, this is the internet after all, and there's always going to be a certain number of trolls, mischief-makers, and silly people.

And there have always been bots, although in more recent times, it appears that AI technology has improved to the point where people can use them as a kind of menace - or a more technologically-efficient way of trolling the internet.

But on the other hand, I've noticed that there are those who accuse other posters of being "bots," but how do they know? I'd hate to think that people are just accusing others willy-nilly just because they don't like what someone said on the internet.