Rhetorically, this is a combination of two things that are inimical to reasoned debate...essentially, the "you're intolerant of my intolerance" argument is cheating. There's a whole host of logical fallacies that let someone "win" an argument by presenting something that can't be refuted simply because it's outside the rules of refutation. But the "you have to tolerate my intolerance" argument focuses on one of two fallacies, depending on how honest the arguer is: binary thinking and false dichotomies.

    Human thinking is very vulnerable to this trap. It's the honest belief that for any particular position, there's only two sides. Yes or no, up or down, black or white...no middle ground. If you're not exactly like me, you're completely opposite. Our language is even structured to support this, there's no graceful way to imply a middle ground most of the time. There's synonyms and antonyms, no sorta-nyms. While we do have middle words for some things (maybe, level, gray, to use the examples earlier), for far too many concepts there's no single word that clearly conveys the idea of being somewhat (fill in the blank). Additionally, use of mitigating adjectives and adverbs has its own trap, implying that beliefs aren't strongly held. ("You're only somewhat tolerant? Then why do you care what I do or say?")

    Specifically, the idea here is that the person admits to being intolerant, but honestly believes that if you're not intolerant as well, you must by definition be willing to accept everything. So if you object to anything at all, you're not a tolerant person, and must be intolerant. Philosophical positions like tolerance are a horrible fit for this linguistically-reinforced mindset, because in truth no one is 100% intolerant, and the only people who will put up with everything are dead or in a coma. But since our tendency towards binary thinking shapes our use of language, complex ideas like tolerance will be pegged so that either the term or its antonym is linked to an unrealistic extreme, while the other word is left realistic.

    So, in our society, "tolerance" is usually accepted to mean being willing to put up with anything and everything, but you can be "intolerant" so long as you draw any lines in the sand that you will not cross or allow to be crossed. Even people who are trying to be more tolerant of others fall into the trap of accepting this impossible-to-meet definition, and are thus easily guilt-tripped when their own lack of perfection is pointed out.

    If binary thinking is an honest problem, false dichotomies are their evil twin. With a false dichotomy, the person advancing the argument may be aware of gray areas, but deliberately frames the debate so that it is binary, making sure to put the opponent's side in as poor a light as possible. They seek out any possible way to "prove" that their opponent is actually on their side of the arbitrary dividing line, and therefore a hypocrite in addition to being on the wrong side of the argument.

    While a binary thinker might be trying to convince an opponent that they're really in agreement (and that they're right), using a false dichotomy is almost always just a smokescreen to deflect the discussion and play to the crowd. They want their opponent to sputter uselessly and let them get away with whatever it was they were doing. Because binary thinking is hard to break out of, this usually works.

    Whether the bigot is honestly engaging in binary thinking, or dishonestly using false dichotomies as a distraction, the fact is that dualistic arguments tend to be simple and make good sound bites. Nuance takes too long to explain, doesn't fit on a button or bumper sticker, and to be honest most people aren't ready to make a nuanced argument to defend an intuitively-held position like "racism/sexism/etc. is bad." Binary thinking leads to lots of great slogans and snappy comebacks, nuance not so much.

    What, then to do? As the great slogan goes, those who don't stand for something will fall for anything. Tolerance is a principle worth defending, but it's not one that should be followed to its extreme "tolerate anything" level. But saying that you stop short of tolerating intolerance just opens you up to a response like, "Listen to yourself! That doesn't make any sense!"

    Instead, point out that your tolerance has limits, and you don't tolerate jerks (or whatever stronger term you feel is appropriate to the venue, such as one ending in -hole or -head or -for-brains). "My doctor says I'm lack-wit intolerant." Then suggest that if they were less intolerant, maybe you could tolerate them.

    This essay has mostly concentrated on rhetorical matters, but the events of 2017 made it important to more closely consider what is meant by tolerance itself, rather than just identifying rhetorical cheating.

    Tolerance is a compromise. Tolerance is people holding onto disagreements and dislikes, but either tacitly or explicitly agreeing to limit how they act upon those opinions. It's an ongoing negotiation which need not change anyone's beliefs, but which can still do so over time...tolerance can become acceptance and even agreement. But it is only necessary that everyone bargain in good faith.

    Those who refuse to bargain in good faith, or who simply refuse to compromise at all, may still benefit from the compromise that is struck...but they are owed nothing. You don't have to tolerate someone who isn't going to accept the terms of the compromise, they are opting out of their own choice.

    If you want something pithier than that: Tolerance is a peace treaty. "You don't start anything, then I won't start anything." How tolerant you are is measured by how bad the provocation must be before you decide the other person has started something.