I actually don't care about the people being discussed enough to look them up and I have little interest in substantiating someone else's claim. If you want me to believe someone is a nasty racist, you can tell me why and show me examples. A huge part of the reason that dialogue is breaking down in the U.S. is because these sorts of charges are so easy to fling out there and too many people take it for granted that they're justified. Worse, too often not taking for granted means you get the label yourself. It's no wonder that the polls missed how closely fought a thing the election would be.
My point about some people feeling justified in conceptually stealing the moral condemnation implicit in a term like "racist", while defining that term to mean something very different than what it does mean, stands without regard to whether or not that this is the case with Twitter and these individuals. No one should trust these accusations until the specific case is actually made arguing for the validity of the charge.
OK, I gave in... I looked the first name up that I came across, and what little I looked at and I tend to agree: it looked genuinely racist. By that I mean that it fit a definition of racism that is: decisions or beliefs about individuals using the non-volitional physical category of race/ethnicity of that individual as a factor in their conclusions. That and only that. Everything else, I said in the first two paragraphs stand.
[EDIT FOR ADDITIONAL POINT] Also, Twitter as a private company has no obligation at all to support/allow any position, even if that position: left or right, reasonable or unreasonable, substantiated or unsubstantiated. It's their ball, they can play whatever game they want. My points aren't about Twitter's rights as much as they are about no longer believing "naked" charges or racism, sexism, etc.