Statistically speaking, men are more likely to be the victims of violent crime than women

We both know that these are mostly men who are looking for trouble. If you're minding your own business, you are far better off being a man and being able to at least somewhat hold off anyone attacking you than being a woman.

Race, sex, overt religious signage, clothing, wealth approximation: They're all factors that should be kept in mind.

I agree. But OP seemed to suggest that the fact that it's almost always blacks is reason enough to be wary of blacks in general. Maybe it is, but that argument goes equally well for men, even for other men as you point out (just like blacks are the biggest victims of other blacks).

But it all matters, and people are able to assess multiple risk factors at once, people are quite good at summarizing traits.

People are even pretty good at knowing when generalities do not apply. When I see blacks in suits, or working in security, I'm not wary of them at all. But when they're bums, or seem to loiter, then very much so.