I said everybody has a little racism in them. Jesus, haven't you seen the movie Crash?
This is actually a point that we went over in great detail in my American Ethnic Studies classes. Everyone makes judgments about the people they interact with based on what makes them unique/different/recognizable. Because of this we often have preconceived opinions and biases based off of a persons race. These stem from the media we consume, the people we have interacted with, and the stories we have heard from people we trust.
We have those same preconceived notions based on the clothes people wear, how people carry themselves, how people talk, how tall someone is or how much they weigh. . .pretty much any identifiable quality.
Side note, I personally felt like Crash was melodramatic garbage, but that is just one man's opinion.