Tragic, but profiling is a critical survival tool developed from birth and it will drive such a result.
Profiling has been given a bad name by the Left, but it is part of rational thought.
When you have no specific information about a particular individual, you make guesses about statistically significant attributes associated with people who look and behave like him.
I will be less wary of a black guy dressed in a suit than a white guy who looks like a bum.