For some reason white people seem to think we aren't angry and violent and aggressive. When you're pointing your finger at someone, there's always three pointing right back at you.
The stereotypes must persist because otherwise white people would have to take a good strong look in the mirror and reflect on the ways in which we have treated black people.
And that will get real uncomfy when we realize that we are literally all the same - good and bad behaviors are literally all just human behaviors.