This sounds a lot like my hypothesis on why ESFPs are the better choice for INTJs than ENFPs. In that pairing, Se is the driver for "calling an INTJ on bullshit" (not that I don't think your TP mind is highly tainted regarding this matter), which at least makes some theoretical sense, as it's bringing in elements of the INTJ's blindspot, forcing him to reconcile/balance out whatever high-minded imaginings Ni is coming up with with a fair dose of Se realism (which, if an INTJ is balanced, healthy, and developed, he should be doing independently, anyway). What's the greater enabler of this ability for an INFP? How is dominant Fi better at "calling bullshit" than dominant Se, or auxiliary Se? Frankly, I never really have associated INFPs with the sort of tough-minded realism that would be useful for calling bullshit on an INTJ. I associate them with strong subjective opinions which are often high-minded imaginings in and of themselves, so how would these really be helpful for "calling bullshit", as opposed to simply forcing the INFP's highly subjective Fi cognitive bias on the INTJ?
Everyone else in here keeps on talking about INTJs and their Te-harshness/bluntness/realism. What exactly are you talking about that needs to have bullshit called on?
(Now it’s my turn to have the INTJs mad at me I suppose.)
There are several reasons for this to be the resulting dynamic.
Tough-minded realism is Se, you’re right. It has nothing to do with that.
INTJs play bullshit with their Fi. On a regular basis. Contrary to what most people think or suppose, INTJs are not unemotional or lack feeling. They feel very deeply, and it drives much of what they use the rest of their functions to do. They often have a set of values that heavily influences their feeling of mission in life, and heavily influences their emotions. However, despite having this and it performing a huge role in their life and actions, because it is lower in their hierarchy, sometimes they experience a disconnect, fuzziness, or obliviousness to it. They sometimes stumble in application of their own values and emotions. This often results in a lot of dissonance for the INTJ, and screws up their equilibrium, and makes them a less effective individual, and hampers their own self-imposed goals, including their Ni vision.
Many INTJs are also prone to depression, very low self-esteem (while seeming confident, even overly so, on the outside to most people), and denying/suppressing/drowning their emotions, especially negative ones. Paradoxically, the more an INTJ tries to divorce themselves or numb themselves to their feelings/emotions, or pretend they have no emotions, the more intrusive these emotions become in asserting themselves and start to spill out all over the place in unhealthy ways.
I think you have an incomplete understanding of what it means to be an Fi dom. It’s not just having high-minded imaginings. We get a whole kit of tools and perks that go with this package.
One of them being, Fi is very attuned to Fi. We constantly have our feelers out, searching and scanning for a match and congruency between our values and the values of others. In addition, we run analysis on an individual’s values and their actual behavior.
Enter Ne as the helping function, and INFPs are natural lie detectors. This includes when someone is lying to themselves as well. Often we won’t say anything about it, but just assimilate the information into the matrix. But if the bullshit threshold is reached, or we see someone we love harming themselves or getting frustrated and going in circles, we will engage on this. How an INFP does it will depend on their own preferences and development. With me, it tends to be very Te, albeit gentle and patient, with a desire not to go there if it is truly not welcome. Ne (being an NF) also helps us - in conjunction with the individual - brainstorm a roadmap for troubleshooting and creative solutions to the problem.
We see the INTJ’s inner drive in terms of their values. We also see their emotions. We see them doing the opposite of what they actually believe, or what they know, even unconsciously, would be in their best interest or health to reach their goals. Or we see them avoiding it because of being overwhelmed and ill-equipped to handle it, causing untold chaos. There is a discrepancy between what they believe, or feel, and even what their Ni and Te would tell them to do, and what they are doing.
Nah dude. That’s some bull-shee-it.
To go back to the movie Onegin, here is a very light and brief (yet momentous) example of an INFP calling an INTJ out on this issue. It happens at the end of the scene, where he is about to exit and go back to the party.