It has nothing to do with income or discrimination.
Yes it does.
You have to look back at how blacks where allowed to buy land and there where conditions on where they could live back in those days,for fear of driving the value of houses down. So they where usually off set away from the city and limited in services. So these areas continue to be areas that are majority black community's today.
If you are limited in education services and everything is rigged against in a subtle way,you are not going to succeed in life. The police have been documented over the years to deal with black males differently than white males and that's just one aspect of how they do not get the benefit of the doubt.
When you are a kid people say that's a bad kid and he gets dealt that way,he does not usually prove them wrong but reinforces that trait. Its the same issue we have today with the reinforced image of a young black male.