While Voltaire defended free speech, I doubt he defended a form that was as absolute as people who quote him make it out to be.
The quote about "I will defend to the death etc." wasn't actually said BY Voltaire, but ABOUT him, by an early biographer.
Here is a quote from the man himself, from his 1763 Treatise on Toleration: “The supposed right of intolerance is absurd and barbaric. It is the right of the tiger; nay, it is far worse, for tigers do but tear in order to have food, while we rend each other for paragraphs.”
An example of intolerance is Goebels on the radio. Or radio presenters calling on the radio for extermination of the Hutu's in the neighbourhood, telling people where and when to gather for that, and giving out pointers on how and why you should kill the Hutu's - as Radio Milles Collines did in Rwanda. Which was absolutely crucial to the genocide taking place. I doubt Voltaire would approve of that and say "oh, it's free speech. We really should defend the right of those poor folk to criticize the Hutu's for being alive."
There hasn't been a single great thinker or writer on free speech who also didn't recognize its limits. Or had a specific purpose in mind for free speech. Only when the debate is divorced from reality, and waged in abstract terms, do we get the pretty weird outcomes we can see today.