Yes, in any 'institution' like this, the idiots, bigots and trolls will sooner or later reveal themselves. The idiots can stay - they're fun, the bigots are fair game and dealt with appropriately. The trolls are shown the door, sometimes several times.

Colour (or other equally arbitrary characteristic) isn't a factor, at least it shouldn't be. Unforunately, this isn't always the case, here and IRL of course, and any predjudice worthy of that title cuts many ways.