It's more about social situation, rather than race in my opinion.
I'm not racist by any means, and have quite a few black friends. Some of them fit the "dumb nigger" stereotype, while others are just your normal average everyday person trying to get by, just like you or me. Unfortunately, the loud minority tends to give a bad name to the silent majority of blacks, especially in the U.S. As that classic Chris Rock joke goes "I love black people, but I hate niggers".

