It is Euro-centric views that put Africans into a negative light, including everything about the culture, i.e. braids. As a Western civilization, whites have associated braids with "trouble", going against the grain. and--gasp!--free thinking.
Even with that said, I tend to see more cornrows on the heads of so called "gangstas"...hell, even the whiteboys that try and be down go and get the braids to somehow associate themselves with the gangsta lifestyle. The question is, does the gangsta lifestyle breed negative thinking, or does the portrayal of black gang members from a media standpoint (movies, TV shows) contribute solely to the way whites think?