The paradox of intolerance;
To be tolerant requires you to be intolerant of intolerance.
If you tolerate intolerance, you are allowing the intolerance to occur, but by being intolerant of the intolerant you do not allow the intolerant a platform to spread their intolerance.
Being intolerant of the intolerance is a stand for tolerance.
Tolerating intolerance is a stand for intolerance.
Notable Questions; & A
Q: " ok then at what point does intolerance of the intolerant become worse than the intolerance one is being intolerant of? This 'paradox' is just a justification for behavior otherwise intolerable. "
A: 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. — In this formulation, I do not imply, for instance, that we should always suppress the utterance of intolerant philosophies; as long as we can counter them by rational argument and keep them in check by public opinion, suppression would certainly be unwise. But we should claim the right to suppress them if necessary even by force; for it may easily turn out that they are not prepared to meet us on the level of rational argument, but begin by denouncing all argument; they may forbid their followers to listen to rational argument, because it is deceptive, and teach them to answer arguments by the use of their fists or pistols. We should therefore claim, in the name of tolerance, the right not to tolerate the intolerant.
Karl Popper in his 1945 book The Open Society and Its Enemies.