> do you think all the human rights, union, indigenous, etc groups control which protests Antifa shows up at? Should they have to self-regulate their protests so no one shows up wearing all-black is allowed to participate?

Of course they should self-regulate - or at least make it very clear when the presence of violently-inclined groups isn't welcome to the organizers. Because the alternative is that the government will regulate those protests instead, which would be a lot worse.