Black people have been killing each other long, long before gangsta rap was even introduced....and it isn't something unique within the United States. It exists as a medium to easily lay blame upon......more akin to blaming Marilyn Manson, Doom, and Grand Theft Auto for school violence.
I'll tell you why crime is particularly high within the black community, coming from someone who worked as a State Corrections Officer and a Probation Officer for 5 years, and has lived and worked amongst or directly adjacent to black communities in Broward County. Ready for it?
Racism, Subsidies, and Human Warehousing.
Racism - Nope, not the perceived notions of a bunch of fat white guys smoking cigars in a backroom wearing cowboy hats. The racism of today is more virulent and complicated. Racism today comes in the form of Statism. Statists include various politicians(mainly Democrats), the Congressional Black Caucus, NAACP, the Urban League, National Action Network, the Rainbow Coalition,Select Black Churches, Jesse Jackson, Al Sharpton, and Jerome Wright. These elitists believe that they alone hold the key to blacks' salvation to save them from(Insert here: racists, bigots, government, the white man, the Man, etc....) perceived enemies. Politicians do it primarily for votes, as pandering to blacks helps them to keep or gain large numbers of the voting bloc. The "civil rights" groups and leaders do it because it makes them money and gives them power........power used largely to browbeat and hustle any major outlet that says anything remotely disparaging about blacks or what these groups are about. The Statists want /i] racism to stay.
Subsidies - Like Ron Paul famously said, When You Subsidize something, You get More of It. Affirmative Action, Welfare, Food Stamps, Racial Quotas, Housing Assistance, and other various handouts are literally destroying the black community. We as a society need to take a step back and realize that inequalities will always naturally exist and that we must treat people as individuals and not as part of a group. With these social programs that were developed largely by statists, they help to keep some members of the black community unmotivated to go out and do something on their own. They'd rather have these members blame something superficial as racism all the while supporting and voting in the true racists that help to truly hold them back.
Human Warehousing - "Tough on Crime" laws and mandates by politicians who cater to largely the richer, gated communities in their districts. Nowadays, you can go to jail or prison on even the most minor of offenses. This is affecting the black community greatly when it comes to incarceration rates as more and more children are growing up without a father figure in their life...and that father figure gets replaced by the streets. You also take a salary out of that community which could have helped to revitalize it and/or keep it in competitive business. Many of these offenses are minor transgressions, and black men are being sent to prison in droves for it. It also doesn't help that many companies won't touch a person who has a criminal background which contributes to the high recidivism rates here in the US.