The datas show that white poors commit crimes in the same rates than black poors.
As a french I really don't care at all about dems or reps, liberal or conservatives propaganda, that's really an only US-centered concern.
Maybe in your country. Why do you assert to know exactly the root cause for this phenomenon in the US? Have you ever lived here? I grew up in Newark, NJ about 15 minutes outside of New York City. Have you ever been here? Or Camden NJ, or Paterson NJ? You probably would not live there for more than 5 minutes.
Anybody that has lived in or around the inner city in a major US city understands the connection between race and crime and how it breaks along community lines. I don't care how it is in France, because you don't have the same population as we do.