We need to include that not only were these stereotypes used to show how we should NOT behave but also as a form of wish fulfillment for white men who depicted us the way they wanted us to be. It is yet another way of white men telling Black people how they need to behave, which is pious, forgiving, sweet natured, and docile. A "Mammy" is basically their ideal white woman.

It is also a way to rewrite reality to absolve themselves of the rape and other atrocities they committed against ALL women of color. So all women of color have the "she is always sexually down for whatever" stereotype because that lets white men off the hook for violating them, But Black women get the extra layers of stereotypes by having their very justifiable rage at being treated like street whores, dismissed as them simply being crazy, irrational, and bitter.