I discovered that one of my friends has something similar - perhaps the same thing - going on in her brain, such that she doesn't rationalise. What we managed to sort out, sort of, was that anything was a justification for her: so when she doesn't eat cookies because it would make her gain weight, and also when she doesn't like Brad Pitt "because he's ugly", and also when she doesn't like a book series because it's chauvinistic, and also when she "doesn't like babies", but her friend's baby "is an exception because it's [friend]'s", these all feel like the same thing to her; she can't or won't tell the difference between what I see as a strong reason or a weak reason or a made-up flimsy reason.

A wild theory appears! In probably the deepest moment of introspection for her in that discussion, she said she thinks she might be like this because it gives her 100% confidence in whatever she's doing. Thinking on that, I'm in the mind of the "70% blue, 30% red balls in the urn" game where some human guessers approximate a 7:3 ratio of blue/red guesses, whereas the best strategy is to guess blue all the time. There might be two kinds of people in this sense: "modellers", who try to accurately mirror reality as much as possible in order to have good predictive skills, and "one-guessers" who commit to the best pure strategy in order to gain the most reward.

Under this wild theory, the one-guessers would have no reason or need to distinguish between the strength of justifications; they'd simply change their behaviour when a better strategy is offered.