Rap or hip hop is a cultural expression rather than an example of what I call "music."
By definition, music has to have three elements - melody, harmony, rhythm. Most examples of rap or hip fail in the melody and/or the harmony aspects.
To each his own and for those who enjoy rap or hip hop, hey, go for it. Not my cup of tea at all, especially when the "cultural expression" involves violence to cops, women, or people. And if the rapper is cutting across the culture with a different message extolling something besides the common "message" associated with rap, all the better.