The Atlantic, Jonathan Rauch makes the case that hate speech contributes to the establishment of new rights. From "The Case for Hate Speech: How Anita Bryant, Jerry Falwell, and Orson Scott Card have advanced the cause of gay rights":
History shows that the more open the intellectual environment, the better minorities will do. We learn empirically that women are as intelligent and capable as men; this knowledge strengthens the moral claims of gender equality. We learn from social experience that laws permitting religious pluralism make societies more governable; this knowledge strengthens the moral claims of religious liberty. We learn from critical argument that the notion that some races are fit to be enslaved by others is impossible to defend without recourse to hypocrisy and mendacity; this knowledge strengthens the moral claims of inherent human dignity. To make social learning possible, we need to criticize our adversaries, of course. But no less do we need them to criticize us.
Dale Carpenter at Volokh Conspiracy applauds, but a comment points out that confirmation bias theory research suggests that Rauch may be too sanguine.