It actually makes a lot more sense to judge someone who belongs to a part of a community or group than to judge someone by the color of their skin.
Meanwhile there are people that are true racists and hate people because of the color of their skin and there are people who just 'hate' those who are trouble and in many communities they happen to be black.
Most of the black people I see in my community I'd be quick to judge.
On the other hand I've been other places in the world where the colored folk are nice, polite educated law abiding citizens.
I have a few black folk in my neighborhood that are the nicest people you'll ever meet.
The same way I've met nice Arabs and Muslims. But enough people start doing something and I'd be a fool not to be extra cautious and suspicious.