The answer to this kind of speech HAS to be more speech, not shutting down this one loon. To often we're on the receiving end of liberal double-speak, "in the interest of free speech, you can't talk because someone will be offended."
Let the loon talk, but speak louder, with more passion and make more sense, the people will get the messsage.
I am all for saying NO to this kind of thing. There is a line crossed when speakers call for Death to Israel, down with the Jews, etc. Freedom is not license.