I feel what you're trying to say, but rap is music and music is art/entertainment. Hollywood makes movies with one white action star gunning down dozens of other white characters. That doesn't mean Hollywood is a friend to Black Supremacists. The fact of the matter is that you're trying to force the word nigga to mean the same thing it did all those years that it was used by white people, and it simply doesn't in this context. The definitions of words are dynamic. There are plenty of words that we use right now regularly that were hurtful and derogatory 100 years ago. That's just how it is. You don't have to like it, but that's reality.
It's silly of you, to condemn a person's work without fully understanding what that work is about. You made this whole thread about Ludacris denigrating the black community with that song, and the song wasn't even close to being about what you are suggesting. As someone said, nigga isn't even being used to refer to black people. It's pretty much being used in a neutral way like "mutha fucka." Rap music does negatively influence the black community to some degree. It also holds a mirror to that community and provides a reflection. It's pointless to try and hold rap and rappers accountable for the ills out there. If you change the community first, then rap will also change in order to reflect the truth. You can say the KKK likes gangsta rap cause it talks about killing blacks, but gangsta rap really does and has always reported the reality. Blacks are out there killing other blacks, and that's the truth whether the music existed or not.