There has been a long list of assholes that people would have gladly shut up at the time that turned out to change us all for the better. Galileo, for instance, wasn't known as the nicest guy. He basically wrote a book calling the pope an idiot. (The guy probably wasn't a genius, but Galileo could have made his point without going that far)

Offhand I could come up with a list of dozen people who were widely unliked by the folks in charge that were critical to our advancement. Oddly, many times the more unpleasant people found their personality, the more important the change eventually brought. They killed Socrates.

ADD: Related fun read for those interested: https://www.amazon.com/Galileos-Middle-Finger-Heretics-Activ...

But whether the root of two actually is an irrational number does not depend on whether you are free to say it is or isn't. In other words, freedom of speech does not mean that there is no way to make any discernments whatsoever between the speech "the root of two is irrational" and "the root of two is rational."