I'd be very surprised if Run DMC sing anything anymore, given that they retired in 2002. And one of them is now dead.
Speaking of rap, remember when Eminem first appeared? It was a novelty seeing a white man succeed in a black-dominated field, and as I recall, it was all anyone talked about when his name came up.
Because it's unusual, and therefore newsworthy. And if you can't understand why the first black president is a talking point, then you really do have a primary school understanding of the media and human nature.
Presumably, you'd also object to those news stories about 8-year-old maths genius winning places at Oxford University - after all, it's ageist. Why should that get talked about more than the thousands of other undergraduates of normal age? Because it's unusual. And that's what news is.