Man A said something racist to Woman B, Charles then stepped in and said "let's have a reasonable phone call and sort this out civilly." What gets more interesting is Woman B has at least one tweet saying "White men in tech ain't shit." So she's definitely racist. edit: (could be wrong about who is who here, but someone involved in getting him banned definitely said the white men in tech comment.)
Charles is getting this hate because by saying to the "Obviously racist" man A, "lets have a civil phone call about this," He's obviously siding with racists instead of siding with the marginalized minorities. (sarcasm)
Charles is getting tons of comments that he should shut the F up and listen to these marginalized groups instead of trying to butt in and make himself look good. Charles is Mormon, 9 Mormons were just burned alive in Mexico, so obviously Charles has no idea what it's like the be a part of a hated, marginalized group.
edit: Sorry it's hard to tell, I'm definitely being sarcastic in parts of this post.
Opinion here, I think people on twitter are working very hard to turn "differing politics" into "unacceptable bigotry." And it's definitely working. It seems the original racist guy mainly has a problem with affirmative action. And he definitely doesn't use current politically correct speech around gender either. But is that grounds for banning a dude just for associating with the "racist guy". I'll leave that up to the reader to decide.