I don't think you were trying to apologize for the cop, brakeman, but I do think believing that race wasn't a factor here is naive. People can have prejudices against black people without actually having hatred for them. I've seen it quite a bit. I'm sure this guy probably thought he could get away with it because the man was black, too. I mean, who isn't going to believe that a black man went for his taser?
Even if the open windows of science at first make us shiver after the cozy indoor warmth of traditional humanizing myths, in the end the fresh air brings vigor, and the great spaces have a splendor of their own - Bertrand Russell