The thing about middle class black people is they cousins. And they kids.

I have seen several times 2 successful black people marry, reproduce, and be shocked to find out that their progeny is a no-good nigger. The way sexual reproduction works, they tend toward the racial mean. The offspring of two high IQ blacks is likely to have a higher IQ than the average black but still lower than the average white. The offspring have a much lower IQ than both parents is not an unusual situation. They try to train the kid, but sometimes DNA wins out. So now you have successful black people living in a white neighborhood with their criminal son. And it brings in the crime.

Similarly, successful black people still have criminal niggers as cousins and lesser-related people that they call cousins. Old timey black families were big, so there can be a lot of these. They also come around causing problems. Sometimes, the successful blacks try to help the poor ones. Like anyone would for their cousin, but statistically badly behaving blacks are worse than others.