actually I lived in Detroit for a while and my brother went to Sloan Kettering in Flint so I've been there too. And yes in areas and among age groups people are prone to violence. And yes those areas are mainly black. And for the most part the saying "around blacks never relax" is the correct way to think. But I will also say there are noticeable middle class black communities that are quiet and peaceful. We also don't self segregate as much or more precisely like people do in Chicago, Detroit and other blue state areas where there is super high concentrations of only white or only black areas with noticeable divides like 8 mile rd. or north v south Chiraq. I'm not saying we don't self segregate we just do it differently and more on a neighborhood bases than entire cities or geographical regions. I think this mixing cuts down on violence because of the white influence and probably more to the fact that anyone who is a non felon resident is allowed to conceal carry does a lot to cut down on crime.
Have you ever been to Philadelphia/Camden or Detroit? If so are people as psychotic and prone to violence where you are now as those places?