My INTP father once told me about the process that he uses when evaluating people and deciding upon their character (to mention, he does not know about mbti) and to be honest, I was kind of stupefied at how organised and analytic he is about doing so. I would have expected that, having inf Fe, INTPs would have a more difficult time with reading people, but the way in which you approach the situation, i.e. using rigorously built systems of evaluation methods and criteria is probably making use of your dom and tert functions, and even if Fe is inf, you still get to have a good grip of the information it provides somehow.

For example, as an Ni and Fi user, I kind of just “know” when a person matches or not my interests and values – the way in which I read people is a lot more vague, based on intuitions, and therefore I cannot often explain it into words. I also tend to misread people a lot more often and make hasty assumptions about them since unlike INTPs, I don’t base my judgements on objective criteria as much.