There's no such thing as "black on black crime." Thats some shit thats been planted in your heads by the media. You ever hear of white on white crime or Chinese on Chinese crime? No. It's just crime. And statistically, people who live/work/etc in the same communities are more likely to commit crimes against each other simply because of proximity. It has very little to do with race. And I won't even touch on the socio economic factors at play.
The bottom line Is, is crime in urban communities something to be addressed? Absolutely. Does it have anything to do with police brutality or BLM? Hell no. It's just another way to shift focus from the real issues.