If you want there to be a law against it, it absolutely needs to be defined. That's how laws work. I don't think there should be a law against it, nobody is making you stand next to a racist person. If they follow you around, guess what? That's harassment, and that is against the law.
Laws against offending people should not exist, because some idiots get offended when someone says "good evening" when they have had a bad day.