As people debate the limits of free speech and whether it should be extended to totalitarians, one should refer to Karl Popper.The Paradox of Tolerance
“The paradox states that if a society is tolerant without limit, their ability to be tolerant will eventually be seized or destroyed by the intolerant. Popper came to the seemingly paradoxical conclusion that in order to maintain a tolerant society, the society must be intolerant of intolerance.”
Philosopher Karl Popper defined the paradox in 1945 in The Open Society and Its Enemies Vol. 1.[1]
Less well known is the paradox of tolerance: Unlimited tolerance must lead to the disappearance of tolerance. If we extend unlimited tolerance even to those who are intolerant, if we are not prepared to defend a tolerant society against the onslaught of the intolerant, then the tolerant will be destroyed, and tolerance with them.