I have sometimes noticed this tendency of INFJ, to reject a logical argument if it doesn't suit them.
INFP's seem more prone to hide from a truth they dislike, even to view that fact or argument as threatening.
I'm an ENFP, and for me at least, I'm pretty quick to recognize the truth in another argument, but I'll argue my side to the very end, or at least until you're so annoyed that I've got you convinced I thought the other way the whole time. I don't do this to be sneaky, I just hate feeling/looking idiotic. Plus, I'll play devil's advocate if I'm bored or don't care all that much about the subject matter, and I even do this unconsciously, if that makes sense, so sometimes I don't even know what I was arguing. (I'm childish and don't like to lose, which probably explains half the trouble)
I've never been good at understanding ENFJ's, so I'm not going to comment on them.
However, I don't think this avoidance of truth is characteristic of NF's by any means. NT's just stop listening to arguments they don't want to hear, SP's just ignore pretty much everything they don't like, and SJ's will just repeat some orthodox mantra or a simple argument until the threatening argument disappears (or the non-SJ walks away to go bash their head against a wall). Humans in general aren't great with unpleasant truths. It's recognizing our own biases and tendencies that's important.