Graham seems to have missed the mark here. What he’s describing as the unjust labeling of x-ism usually isn’t related to the deviation from a norm, insomuch as it is the prejudices behind that deviation. He argues that truth is ignored, but it’s not the truth that’s usually at issue in such matters, it is the manner of delivery of whatever truth may be, filtered through a set of prejudices the hearer is offended by. The hearer then can either utilize the thought terminating x-ist label, and walk away, or attempt to address those prejudices directly. In the former, they are saying, “because I have identified these prejudices in the way you’ve presented your case, I cannot give credence to any of the truth you are arguing”. Reasonable, but less than ideal. The latter - and often better response is, “that’s x-ist and let me tell you why.” That’s how you cut through the BS and have a productive conversation. I hope this is what he was trying to convey, but didn’t quite get there.

What he seems to have missed in separating truth from prejudices is important to recognize. This is an expected communications problem in a society that struggles with decency, and decency is what’s at issue here - not truth. Because at least one party lacks decency, they’ve lost their credibility to convey any truth. The other party may lack tolerance, but that intolerance is, at least usually, about those prejudices, and not any underlying truth.

Regardless, actual heresy - of the biblical type that Graham is trying to use to support his argument here - has historically been more based on threatening a power structure, such as was the case with Martin Luther, for example. Ironically here, the tables were turned, and the “heretic” (Luther) presented factual information while it was the hearer that reeled with prejudice. The two cases are about as much alike as a camel and a spork. I am surprised he tried to make the comparison. Nonetheless, if that is what he’s trying to argue, then he’s seemingly suggesting the fault is always on the listener for being offended. In the cases Graham is describing though, it is far more likely to be the speaker who wraps whatever truth there might be into vitriol brought into the conversation. It at least would have made for a good essay to point out both possibilities.

Tl;Dr: truth always falls victim to prejudice, on either side, which is why we should work to identify and root out our own prejudices before engaging.