You don't have to be black to understand that George Zimmerman's shooting of Trayvon Martin was based on racism.
George Zimmerman announced his fear, suspicion, and hatred of blacks in his initial conversation with the police. He voiced his fear of Trayvon because he was black, wearing a hoodie, unknown to him, and also young. He "knew" he was "up to no good" and didn't wan't him to get away, because "that kind, (xxxx blacks), always do."
George Zimmerman's epithets clearly expressed his fear, suspicion, and hatred, not of Trayvon as an individual, but of blacks as a group. That is racism.