Why is there so many black neighbourhoods filled with poverty and gang violence?

I'm from the UK and here it's full of white gun crime, stabbings, gang violence an stuff, but whenever I listen to rap it's all ghetto black people, the only white rapper that really made it (apart from vanilla an beastie boys) was eminem, there's thousands of underground and mainstream black rappers talking about the ghetto, I've watched like ever episode of 'Hood 2 Hood' and from all USA states that were visited it didn't show any white ghettos. All the black dudes in the hood 2 hood series are just like working class whites in England. So what's the deal? why are black neighbourhoods like this? Obviously there is lots of wealthy blacks and poor whites, but I just haven't seen much ruff white america yet, apart from the skinheads that's about it and maybe trailer parks, but I'm talking about projects and housing estates that are full of white gangs or just white criminals.