You're begging the question here, assuming that what is called hate speech is necessarily harmful. I am quite certain that in the US political climate much of Palestinian political speech would easily be considered anti-semitic hate speech. Whether you consider this speech the valid outcry of the oppressed, or hateful bigotry of terrorist sympathizers, depends on your political perspective.

There is no definition of hate speech that is simultaneously objective and useful. If you can use it against your enemies today it can be used against you tomorrow.