List of groups blacks have horrible relations:
1) Asians
2) African Blacks
3) Jews
4) Light skinned blacks vs Darker blacks
5) Crips vs Bloods
6) Urban Blacks vs country blacks-—I’ve seen it close up
7) Mexicans
8) Indians(India)
9) Islam(see Darfur)
10) east coast rappers vs west coast rappers
Ther reasoning that I hear is that Carribean/Africans are "not authentic blacks", or some such nonsense. Usually you hear this when an African or Carribean who, after a few years of living in America, is running circles around the American blacks who have been here for hundreds of years.
"How can that be in a racist America?", the black American would say. So instead of answering that question honestly, the immigrant black is simply deemed "not authentic", and it's back to the "racist America is responsible for my woes" excuses.