Another coded term that means stereotyped angry black woman. If someone is angry, they are angry, black or white. It's just a "clever" way for The Right to try and make Mrs. Obama out to be "ghetto" at heart. It really bugs them to have a Black First Lady, especially one that is smarter and more articulate than the white ones that preceeded her.
They would rather prefer a woman who was "servicing" a married man just before he would go home to his wife, as thats the standard for morality they hold.
Peace.