i've spent a lot of the evening researching this comment relating to porn. so i'll leave you to read through that and some of the related links.
on the topic of hate speech, here is a comment from catherine mckinnon, from her book, "only words":
“We argued that group libel, most of it concededly expression, promotes the disadvantage of unequal groups; that group-based enmity, ill will, intolerance, and prejudice are the attitudinal engines of the exclusion, denigration, and subordination that make up and propel social inequality; that without bigotry, social systems of enforced separation, ghettoisation, and apartheid would be unnecessary, impossible, and unthinkable; that stereotyping and stigmatisation of historically disadvantaged groups through group hate propaganda shape their social image and reputation, which controls their access to opportunities more powerfully than their individual abilities ever do; and that it is impossible for an individual to receive equality of opportunity when surrounded by an atmosphere of group hate.
“We argued that group defamation is a verbal form inequality takes. . . . We argued that group defamation in this sense is not a mere expression of opinion but a practice of discrimination in verbal form, a link in systemic discrimination that keeps target groups in subordinated positions through the promotion of terror, intolerance, degradation, segregation, exclusion, vilification, violence, and genocide.