So, at risk of getting into a very long discussion...
In the 50's and 60's, blacks were essentially only allowed to rent in ghettos that were very close together and clumped. Extremely high density, extremely high population totals, very little space.
Even now, I would say very large, very dense cities tend to be disproportionately black. That's a history lesson for another day, but in any case...
These areas are vastly easier to police due to the closeness and the proximity of all the people. I would venture to say that if we looked at the whites crime rates in the inner city vs the suburbs, the crime rates for white people would be vastly higher for the inner city. Similarly, if you could find a predominately black suburbs, I bet the crime rate is vastly lower than the inner city.
Living in a large city just isn't favorable to anyone, in my opinion.