If I may, l'd like add Racist C, who, like Racist B, is not, at core, racist. They operate from a place of absolute antipathy; not malicious intent, because they don't care enough to actively dislike, let alone hate. This may come from a simple lack of exposure to a world other than their own, or from other factors. It may be that these folks are easier to reach than any other kind, by the simple expedient of broadening their horizons - It's a lot harder to justify voting for a party of bigots when your children play with your Iranian neighbours' children, and everybody on the street goes to the barbecues hosted by the gay Eastern European couple.
Like the B's, something needs to be done about the C's. But calling everybody A's will get us nowhere - real changing of minds happens between people, not between angry Twitter avatars.