To oversimplify, Ti governs selection and honing of ideas. If the INTP is mature (if Ti is well-fed and well-informed by Ne of the ways of the world), then the INTP can express his/her Ti ideas in the world in a manner that suits real-world conventions for maximum effect. And the mode of expression needn't be criticism. If the Ti is well-informed by his Ne, the INTP will have a number of real-world conventional modes of expression just like anyone else.
On the other hand, if Ti is isolated and Ne isn't informing it of real-world conventions, Ti won't be able to express itself as described above. The modes of expression will be increasingly maladaptive. Defensiveness will probably be at the base of the maladaptiveness, although the Ti thought can be expressed any number of maladaptive ways including rants and pre-emptive attacks. INFPs work much the same way. If Dominant Fi is isolated and Auxiliary Ne isn't informing Fi of real-world conventions, the way of expressing Fi values will become increasingly maladaptive.
The maladaptive modes of expression aren't always or necessarily Ne-based. Stressed-out people may indeed work from or react to their shadow Tertiary or Inferior functions as well as the immature Auxiliary. Nonetheless, in the case of INTPs and INFPs, I think some modes of expression can be identified as based on immature Auxiliary Ne in particular.
Let me pick on INFPs first. I'm an INFP with an INFP wife, and I've even had INFP subordinates in the workplace. (In fact, my interest in this subject and thread springs from wanting to get a better handle on immature INFP Auxiliary for purposes of my marriage.)
Anyway, I feel I can quickly identify a couple easy and notable examples of immature INFP maladaptive use of Ne, ranging from almost playful to thoughtless and potentially destructive. For example, 1) Whimsicality can be entirely playful, but it can also be used in a "dazzle 'em with your footwork" manner to turn up one's nose at critics; 2) Immature INFPs can also make extravagant and even ridiculous claims to spiritual or personal insight or extravagant crusadership in a "baffle 'em with your bullshit" manner when subjected to more direct criticism; 3) When feeling put upon, INFPs can play the victim so convincingly that even they believe it, with or without any real foundation to the claim; if pressed on the point, the INFP can drum up paranoid and far-reaching rationales to defend their victimhood.
These are just a couple examples of INFPs using Ne maladaptively, and I'm sure old-timers from INTP-C will remember examples of those behaviors from occasional INFPs wandering through. To me, the particularly Ne flavor of these examples is in how they mimic the playfulness of ENFPs or the reactive fencing of ENTPs (Ne-Dominant types), albeit in a less skilled and more defensive capacity.
Parallels for an immature INTP using Ne maladaptively: 1) Playful derision, role-playing, word play, and logic play that can be used in a "dazzle 'em with your footwork" manner to turn up one's nose at critics (IOW where a Ti idea is expressed, but couched maladaptively in the sense of retaining deniability and having the option of turning accusation or misunderstandings back on the listener); 2) Using cutting derision together with claims of special insight when pressed more closely; 3) Rigid insistence on a lone principle, sometimes to the point of absurdity, using fantastic and far-reaching sophistry of the angels-dancing-on-head-of-a-pin type to defend the principle.
Again, these tactics aren't maladaptive because of the presence or absence of legitimacy in the Ti idea they are expressing. (A careful listener can usually find a legitimate idea or need of some sort lurking behind the defensiveness and BS of the mode of expression.) Rather, they are maladaptive because the mode of expression doesn't take into account real-world conventions.
And I consider these examples to be Ne-related much the same as their INFP counterparts: they smack of the playfulness of ENFPs or fencing of ENTPs, albeit in a less skilled and more defensive capacity.
PersonalityPage.com basically sets adaptability to Fe real-world conventions as the acid test for measuring maturity of a given INTP. (See below.) The more an INTP adapts to real-world conventions in his manner of expression, the more evidence he demonstrates of maturity and a Ti properly informed by Ne. Conversely, use of only one or two abrasive or derisive modes of expressing ideas would be strong evidence of an immature INTP whose Ti is isolated and uninformed by Ne.
One sees INTPs with huge differences in their adaptability to Fe conventions at INTP-C and even here. Some INTPs have only one or two modes of basic expression (monotone, derision, abrasiveness, sophistry, etc). Others are clearly better able to adapt their tone and manner to the context and the audience, signaling a better awareness of real-world conventions and a higher level of type-related maturity.The INTP's inferior (fourth) function is Extraverted Feeling. This means that the INTP is not naturally in tune with how other people are feeling, or with social expectations. In fact, the INTP is likely to reject the importance of social rituals, rules, and expectations. This is a natural weak point for the INTP, which no doubt causes strife to the INTP and their love partner. This weakness can be overcome by developing their Extraverted Intuition to the point that they can perceive Feeling type expectations in the external world. They don't have to use Extraverted Feeling to understand how to act in situations. They can perceive the expected behavior from their Extraverted Intuition function. However, if they are restricting their incoming data to only those things that support their existing way of life, then they are not learning from Extraverted Intuition at all. [...]
INTP Personal Growth
Which brings me to my criticisms of you in particular. You operate almost solely in a dry, critical mode and admit to a "fetish for criticizing." Justify it anyway you want, but traditionally that kind of long-term unwillingness to tailor your tone to the audience is evidence of immaturity and lack of adaptability to Fe real-world conventions.
Also, the point about Fe being a "natural weak point" for INTPs (from the PersonalityPage.com quote above) makes your protestations about the insincerity of Fe in INFJs seem all the more overdone: "...appeasing their own vainglory..." "...its manifest to me that they're putting on an act..." "Their crime, in this respect is against the essence of feeling." An INTP dogging INFJs about a petty issue like immature use of their Auxiliary smacks of immaturity on the INTP's part. You protest that your motives are pure and your maturity is developed enough that you have no particular axe to grind. But it sounds like the fox trying to explain why he is hanging around the hen house. Saying that he has matured and no longer has a taste for chicken isn't really convincing under the circumstances.
I'm sure you're aware that I have other reasons (personal perceptions of your intellectual style) that make me doubt whether you're using your Ne maturely. We have argued them previously to some extent. But I'll stop here. The post is running long; and if none of my arguments thus far get through to you, then more of the same won't help.
I would like to make one request, though. I've tried to describe a couple examples of how INTPs and INFPs tend to demonstrate immature Ne as a defensive or maladaptive mechanism (IMO, of course). No matter if you agree with me or not on whether those examples are Ne-based, I would still be interested if you could provide some similar detail and examples as to how you perceive immature use of Auxiliary Fe in INFJs. I have my own perception of Fe in INFJs, but Fe isn't my Inferior so my perception of it is rather vague. I mainly just notice immature Auxiliary Fe in its most extreme form, when INFJs occasionally get rigid and angry on some specific issue of importance to them. As long as the subject is in play, I would be curious to hear some examples of what exactly you're perceiving as immature Fe in INFJs.