Black on black crime is a platitude. The fact is 90% of the time the victim knew their killer and that killer was the same race as them. There was so-called "black on black crime" in the days of slavery.
It may be economic, territorial, or simply confrontational. As Jay said, 'where personalities clash and chrome meets chrome." But it s hardly a racial problem. Its like people imagine these drawn out urban conflicts with dark and lighter-skinned folks pitted against each other. Please. This ain't Haiti.
So appeals to racial unity fail to address the point. For instance, Rev. Jackson thinks in the wake of Travon's murder we should have a national conversation about "black pain." I'm thinking, fuck black pain, how about addressing the states passing these wild ass gun laws. You can gun down unarmed teenagers in central Florida and walk away with the murder weapon scott free? Fucking insane. Even race as a motivating factor is still rather secondary.
People inject race into it, I think, to abstract the situation as much possible. And of course draw attention away from the underlying problems: the job market, redlining, health services, huksters, etc. Plus repeating "black on black crime" allows people to constantly insinuate violent criminality is something innate or intrinsic to minorities.