I think it better that you empty the streets, provide no news coverage and let them chant their racist slogans to the emptiness.  If they violate someone's rights or break the law, then arrest them.  They have a constitutional right to voice their perverted views, but if no one is listening, they will go away realizing only a very small percentage of the population supports their views.  Our problem is that the media uses these events to whip up viewer sentiment to manipulate the public into believing they need to take some sort of action.  Sorry, but knocking them down would make you as bad as them....better to let them see no one is listening or even cares.