Hate speech (or writing) fosters criminal actions up to and including genocide. But even the 'smaller' acts of mindless cruelty that 'hate expressions' (which include writing, graphic art, and film) promote are themselves objectionable and often criminal. At the least it debases life.
It is especially dangerous when it has the sponsorship of a State, as in Nazi Germany, when it becomes the sole means of 'discovery' of what people are like. That is, people who are not to be seen with inherent value for their humanity. But when a mass movement peddles hatred, all sorts of horror are possible.
Hate speech is not a transitory defamation; it is often the result of concerted effort to degrade pariahs so that they can be abused or even exterminated. Whether in Nazi Germany or during the Rwanda genocide, officials inundated perpetrators with material that made killing helpless people seem not so bad as it would seem after the act.
Not all speech has the protection of the First Amendment. Criminal speech -- that is, speech intended to perpetrate such a crime as robbery -- is not defensible in a court of law. Yes, it is permissible to depict criminal conduct in a drama, but in real life, "Your money or your life!" is evidence of commission of a crime (robbery) if it is uttered in the context of a robbery. Urging people to harm or kill others for what those people are is perpetration of the crime itself if the crime happens.
