I think we all project.* In other words, we all start our understanding of another person by assuming others behave as if they (in terms of MBTI / cognitive functions) have the same agendas that we have.
In other words, the power of these forums can be to realize what agenda one's own cognitive functions are serving... and what agenda is being served by other people's cognitive functions.
Real self-actualization, at least as it seems to me, is to be aware of these cognitive function dynamics and appropriately ascribe motive NOT based on one's own motive, but instead based on the motives of that person's cognitive functions.
Specifically, in relation to your example of an INFJ / Fe-user who judges the highly emotive behavior of the ENFP / Fi-user as indicating that person as "nutso", this has happened to me in real life. I had an INFJ completely misinterpret my behavior because he was judging it from his perspective as an Fe-user. This was certainly his right... but the cost he paid was that he missed out on what could have been a wonderful friendship. He didn't understand that my willingness to express my innermost feelings wasn't evidence that I was crazy. Instead, it was a normal byproduct of my Auxiliary Fi and my Extroversion. <Sigh.>
*From Wikipedia: "Psychological projection or projection bias is a psychological defense mechanism where a person unconsciously denies their own attributes, thoughts, and emotions, which are then ascribed to the outside world, such as to the weather, or to other people. Thus, it involves imagining or projecting that others have those feelings."