I'm sure that everyone here will agree that freedom of thought and speech is very important. I'm also sure that eve... well, most people here will agree that there are ideologies that caused an enormous amount of harm (nazism being the most commonly accepted example, communism and especially stalinism being another). Isn't there a contradiction here? How relative is freedom of thought and speech? Do ideologies that directly threaten freedom of thought and speech have to be censored to ensure survival of said freedom, or does that, on the contrary, directly lead to its destruction?

Also, as always in political-ish threads, keep things civil and realistic, please. No illuminati, no insults.