But if you have ever tried to live your life this way, you will have seen it fail: “Why won’t you tolerate my intolerance?” This comes in all sorts of forms: accepting a person’s actively antisocial behavior because it’s just part of being an accepting group of friends; being told that prejudice against Nazis is the same as prejudice against Black people; watching people try to give “equal time” to a religious (or irreligious) group whose guiding principle is that everyone must join them or else.
Tolerance is a social norm because it allows different people to live side-by-side without being at each other’s throats. It means that we accept that people may be different from us, in their customs, in their behavior, in their dress, in their sex lives, and that if this doesn’t directly affect our lives, it is none of our business. But the model of a peace treaty differs from the model of a moral precept in one simple way: the protection of a peace treaty only extends to those willing to abide by its terms. It is an agreement to live in peace, not an agreement to be peaceful no matter the conduct of others. A peace treaty is not a suicide pact.
Compare that to the many statements that unless you tolerate everyone and everything, from NAMBLA to Nazis, you are not truly tolerant. While so many of my fellow liberals are hung up trying to catch the Alt-Right in logical fallacies, they slipped and fell for a classic. This idea that to be truly tolerant, you must allow hate and depravity feels wrong precisely because it is. As usual, the people that control the definitions of our words, control the conversation. Tolerance is not blind acceptance. It is a method of establishing social order.
I highly recommend reading the Zunger article, several times. I also recommend that it's not a given to just read it and accept it at face value. But it is a good start for developing a new shared definition of tolerance.