This... may not go over very well, but I don't think people's issues with sanders can entirely be chalked up to racism; the complaints I've seen have mostly had to do with the fact that in I think the top post (or one of the top posts, at least) on her journal she calls herself something along the lines of "bitchy, snide, and cruel" and says that she'll send her "minions" to dogpile people who make comments on her journal that she finds offensive or annoying. And so people aren't sure that's the kind of person they would like to have representing fandom.

Granted, I don't know her and haven't been following stuff that she's said, so maybe she is a lovely person (and/or angry only in a necessary and righteous manner) and that's all being taken out of context and blown out of proportion due to subconscious biases. And regardless of her behavior, it may very well be that she is getting comments that are way out of line and racist (I couldn't say for sure without links to or quotes of said comments, but it is depressingly plausible). But based on what little I know, I do feel it's a little disingenuous to frame all criticism of her as "people are telling the angry black woman to shut up!"