Indeed, INTJs probably make the mistake of interacting more with that inner robot than with the Fe.
Not really, the Fe is pretty refreshing to me. And I think the Te in INTJs is refreshing to the INFJs. It's a mutual relationship, both secondary functions feeding the others third function. With Ni supplying the understanding, which is important, because Ni is very important. Personally I feel distant if someone doesn't understand or trust "gut instincts."
On the Te-to-Fi idea, I mean something like, such Fi as is there is (something like) in service to the Te, so if Te is ignored, Fi is... adrift?
I always though of the functions like this (but I'm not an expert):
~First function feeds second and third.
~First and second are how the individual primarily deals with the world.
~Third is relaxing, although it is third, and not as powerful or developed as the first and second. I think it's called the "aspiration" function?
~Fourth is what acts up when the individual is stressed. Largely ignored.
Hmm here is an intersting site I just found,
My MBTI Personality Type - Understanding MBTI Type Dynamics - The Eight Function-Attitudes
and
My MBTI Personality Type - Understanding MBTI Type Dynamics
Thinking probably won't answer a why question about tertiary feeling, but feeling will promote a particular line of thinking direction... maybe. Feeling will help you choose one strategy over another? So ignoring such plans and strategies and ideas the INTJ has, is in fact ignoring the feeling he has?
When you ignore an INTJs strategies and ideas, they are probably more tied into Ni not Fi. If an INTJ had to choose one strategy over the other they would probably rely on their intuition not their feeling. Although Ni and Fi get mixed up a lot, and I'm just as confused as most people about that one. It's hard to place labels on things with INTJs when differentiating between Ni and Fi.
I guess this confusion is summarized by the old saying,
"It's just my gut feeling."
Is that intuition or feeling? Heh.