It is a slang term associated with black culture. The reason why it became a running a joke in -- and the title of -- the movie "Baby Mama." Remember that movie? The black guy explains what a "Baby Mama" is, and tells the naive white woman to "ask any black man." Remember that? You brought the movie up.
The fact that elements of white culture have co-opted the terminology doesn't change any of this. Your friends use terms like "fo shizzle" and "Baby Mama." Good for you guys. But would it be racist for FoxNews to put "fo shizzle" up on the screen when Obama is talking? YES! Would it be racist if FoxNews took a poll and asked the public if they would vote for "Obama-dogg?" YES. It would. For the same damn reason it is racist to put ghetto slang like "Baby Mama" on the screen in reference to Obama's wife. I know white guys who say crap like, "What up, niggas." Does that make the N-word fair game for FoxNews?
FoxNews took a black slang term that has become a joke to the world and they attached it to the wife of a presidential candidate who is black. And you are seriously going to pretend that there is no racial issue there?
Ideology over reason. The story of modern American politics.