The “tolerance paradox” is a handy tool with which to justify violence by those on both sides. If I’m just fighting intolerance, then my actions are justified. It’s a common rally cry used by authoritarians to stamp out diversity and democracy. To really hammer the point home, the Nazis were the first to employ it. By blaming their issues on the “intolerance” of foreign states, they justified a global war. It is obviously the inspiration for Popper’s 1945 work, The Open Society and Its Enemies. Russia is currently using this fallacy to justify the war in Ukraine, claiming that the West is “intolerant” of Russia, and they need to defend themselves against this intolerance.

Here is a full quote from Popper on the subject if anyone is interested.

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 most 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.

Popper’s argument is laid bare here. Tolerate up to the point of violence. That is, if one physically attacks us, we no longer have the burden of tolerance. Popper is commonly misquoted and intentionally misused to justify violence against disagreement, and that is clearly not his argument.