Guys, stop overcomplicating things. A huge share of blacks in this country simply believe, "If you disrespect me, I'll kill you." That's it. You could maybe add that they believe whites have disrespected them just for existing. But blacks kill each other every single day in exactly the same way that Karmelo killed Austin. Just this week a black man killed another black man on the bus for asking him to turn his music down.
Others have commented on what we often consider gang violence is really just petty squabbles that turn violent. I think even people who understand the murder data in this country need this explanation because, while we still don't condone gang violence, we understand it. The problem seems much worse when you say that it's actually just random violence over minor confrontations!