I'm not entirely sure the comparison is valid. Music tends to have a greater cultural influence than video games. Not to mention having real-life idols that proscribe to the 'gangsta' way of life. In fact, I think its people rather than the music that causes the deeper cultural influence.

Admittedly, gangsta rap that describes the ways of inner-city life is an artistic statement. I suspect the parent was talking about the certain sub-genre of gangsta rap that eulogizes and encourages a violent life.

To answer your first question (even thought you asked the parent), I can't believe that music of any form can possibly be the cause of ills among the black community.