The notion that censorship is a tool to combat slavery is absurd. The opponents of slavery only were able to defeat it because they had guarantees of freedom of expression. Countries with robust protections of freedom of speech were the first to get rid of slavery.

As for Holocaust denial—it’s flourishing at precisely the same college campuses that impose the most severe controls on speech. Settings where groups actively use censorship to silence each other are inevitably those with the worst cases of hostility and violence.

That shouldn’t surprise anyone. Censorship is always linked to domination and control—that’s its very purpose.

You really need to study the historical record, and grasp how freedom of speech actually works. It’s censorship that constrains truth and undermines human rights. Allowing individual freedom of expression is how tyrannies and abuses are defeated.