There are many other clues that clearly make them bots: obvious LLMisms, parroting canned talking points, accounts based in developing countries with nonsensical profile bios, ...

But even without all that, it's very hard to believe that suddenly Twitter attracted all the 4chan-level far-right cesspool organically, and that these people have nothing better to do than replying to any post getting traction from people that should be completely outside their interest circles.