The charge of intolerance has come to wield enormous power in much of Western culture – at least as much as the charge of “communist” during the McCarthy years. It functions as a “defeater.” A defeater belief is a belief that defeats other beliefs – i.e., if you hold a defeater belief to be true (whether it is true or not is irrelevant), you cannot possibly hold certain other beliefs to be true: the defeater belief rules certain other beliefs out of court and thus defeats them. For instance, if you believe that there is no one way to salvation and that those who think there is only one way to salvation are ignorant and intolerant, then voices that insist Islam is the only way, or that Jesus is the only way, will not be credible to you: you will dismiss their beliefs as ignorant and intolerant, nicely defeated by your own belief that there cannot possibly be only one way to salvation. Your belief has defeated theirs.
So if a Christian articulates a well-thought-out exposition of who Jesus is and what he has done, including how his cross and resurrection constitute the only way by which human beings can be reconciled to God, the person who holds the defeater belief I’ve just described may listen with some intellectual interest but readily dismiss everything you say without much thought. Put together several such defeater beliefs and make them widely popular, and you have created an implausibility structure: opposing beliefs are thought so implausible as to be scarcely worth listening to, let alone compelling or convincing.
D.A. Carson, The Intolerance of Tolerance (Kindle Edition)