I'm pretty sure that if they are doing that on Lemmy, it's not without a human in the loop. I've been doing some experimentation with it, and I don't think it's a fully automated response.
I have some thoughts on it, along with a whole series of unfounded Fediverse conspiracy theories. I don't think they are doing fully automated bot responses. They might have LLMs helping to craft long, hostile messages that always carry the right framings and narratives at scale, but there wouldn't really be a way to detect that as far as I can see, so I'm not sure how much it bears thinking about. I do think systematically hijacking posts and making sure the comments look "right" is part of their system.
Take a look at this:
They're victims too. They had so much propaganda, and so much bad education, and so many legitimate grievances about a government that since the 1990s at least has mostly forgotten about them.
I try to be kind in my thinking. They might attack and someone might have to defend against them. They might get attacked by the same system they supported in the beginning. A lot of them are going to get hurt, some of them very badly. None of that is good, even a little bit. Some of it "has to happen" and some will just happen because it happens. But I don't hold any of it against them nearly as much as I do against the people at the top that engineered this whole thing on purpose, with full awareness.