Racism is a crime as well. I wouldn't call anyone racist without knowing them very well.
That's utter hogwash and you know it. In what country, is the subjective state of being racist illegal? Can you cite the legal code from your country and verify your statement as fact? If you're citing an act of libel has been set upon you with said labels, then that's completely different then saying the act or state of being a racist is illegal.
Besides, even if you change your username, you still have your posting history still in existence. You will still have your naive questions on race and predjudice tucked under your "My Posts" and "My Topics"....