Per WikiPedia, the paradox of tolerance is stated as such:
If a society’s practice of tolerance is inclusive of the intolerant, intolerance will ultimately dominate, eliminating the tolerant and the practice of tolerance with them, and thus, in order to maintain a tolerant society, the society must retain the right to be intolerant of intolerance.
There have been attempts to resolve this paradox, but they usually overthink and over-complicate it. There is a much simpler solution.
Tolerance doesn’t exist in a vacuum, people don’t tolerate things just for the sake of tolerating them. The purpose of tolerance is to prevent, reduce, and minimize harm.
For example, instead of fighting with a neighbor who is making noise during a birthday party, you tolerate it until it’s over or close your windows. Instead of seething and stressing that someone else got the job you wanted, you tolerate and accept the fact that you can’t always come out on top. And so on.
Tolerating intolerance however, INCREASES harm. Tolerating a bully allows them to continue to bully their victim for being different. Tolerating a domestic- or animal-abuser, allows them to continue doing harm. And of course, this applies to lesser and greater forms of harm.
Not tolerating intolerance accomplishes the true, underlying, ultimate goal of tolerance of preventing and reducing harm.
Tolerating intolerance allows the intolerance to continue indefinitely. Not tolerating intolerance is a temporary action to put a stop to the intolerance, so ultimately, not tolerating intolerance results in LESS intolerance overall.