It's difficult to pull one thing out that would explain it all, but what at once impressed and dismayed me at once was the idea that the "extreme NT" view of the world consists not of beliefs based on logic but on social consensus, which become more or less "true" depending on the confidence with which they're expressed/denied and the status of the speaker, and that NT's in conversation are usually dealing only in these cultural symbols and their connection to the NTs' identities rather than thinking about any real thing to which the words should refer. I don't know if I communicated it really clearly there, though, maybe someone else can do it better.
An example of a situation it would explain to me, though, would be the way people tend to debate politics: one person might make a statement about abortion and the other will "debate" by saying something about gay marriage: two completely unrelated topics, but NT's see no problem with lumping them together because they are linked in the cultural reality. Or someone might make a nuanced, middle-of-the-road statement about, say, gun laws, but a pro-gun-control NT will react as though he's talking to some gun nut and an NRA member will fire back stereotypes about "liberals". It's not the arguments that matter but the attack or support of a predefined group the person identifies with, and the other person is either an ally or an adversary.