Honestly, there some white people who are afraid of black people, that's considered a form of racism because black people are no more violent that white people or any other race.
There's a problem with that, though. You see it's in literally everyone's minds, due to evolutionary reasons, that black people appear slightly more aggressive. In some people this is exacerbated, and in some it's less apparent, however it applies to everyone. By that definition then, literally everyone on the planet (Except maybe a very small few who don't register fear) is a tribal. If that's all you're trying to prove then your point is pointless.