This piece, currently available at The Root, posits an interesting thesis: that the label "black-on-black violence" is an unnecessarily racialized view of problems that are really socioeconomic in nature. From the op-ed:
At this particular moment in our history, it is more important than ever to reject these kinds of racialized explanations. They are being used to slander public school children as incapable of learning; to deem affordable housing a hopeless cause. In gentrifying cities, ''black-on-black crime'' is used as a weapon to encourage public policies that treat black people as blights on the new urban aesthetic. There is a moral imperative to challenge these assumptions.
I've not fully thought this through, but I thought the piece made some good points (after all, have you ever heard a crime described as "white-on-white violence"?) that might be of interest to our readers.
And with respect to the linked Enquirer article: I should note that apart from the headline, the article doesn't use the phrase at issue. And, in fact, the body of the article does a pretty good job of exploring the socioeconomic causes of urban crime.