I put this paradox under the banner of logical fallacy.

Since what is described as "tolerance" can be defined by the cultural norms of a certain society, what is marked as "intolerance" is entirely subjective to the society handling said "intolerance". The idea of what qualifies as "intolerance" is not absolutely transferable between societies, and such, no universal definition can exist so long as multiple societies cohabit this planet. With there being no concrete definition between societies, you can never properly define "intolerance", and therefore never be justified in your own intolerance towards "intolerance".

Declaring that some intolerance is necessary opens the door for conflation of what is deemed as intolerance based on other unrelated subjects. A good example of this would be the current year Marxists. According to the history books Nazis are the most recent examples of "intolerance", however these marxists view all forms of anti-neomarxism as akin to Nazism, therefore it's perfectly acceptable to them to be intolerant to people who are against neomarxism, because to them they are no different than "Nazis".