Why is racism such a taboo if it is true?

Like black people and dishonesty. My wallet must have fell out of my pocket on the bus yesterday (if some black person didn't pick pocket me) and I know damn well I won't get it back due to the fact that there weren't many good samaritan looking white people taking the bus. So i don't understand why I am considered the bad guy when that I am saying here is true. Not only is it not really honest its mostly just lack of thinking outside the realm of yourself in order to do something considerate for someone else, something you would want someone else to do for you if it so happened.