Do you see why we might need to do this sort of typing? The reasons we might resort to what you might see as gross stereotyping? That while the instrument may be extremely lacking in your estimation, it would be exceedingly helpful in ours? Much like someone who for whatever reason does not drive a car may see cars as clumsy nuisances, does that mean that automobiles are not still effective and useful for many people?
Things have to make sense for us. Notice the word "have" there. It is quite literally a psychological need for things to make sense for us. When things don't make sense, it causes psychological pain, and this is not an exaggeration. What other types experience as "frustration" our types experience as a combination of rage at not understanding, pain at the barriers put up in our minds and our seeming inability to use it as normal, and agitation at not being able to get past something that should be so simple. We see human interaction being incredibly simple for so many people. It's not so simple for us, as our ways of thinking and interaction run contrary to many people in the world. Other people frustrate us because they consistently do things other than what seems logically consistent, and then when we ask for an explanation (to establish a rationale within our minds and reconcile the situation with what we already know), people become upset and act like we're cold and uncaring.
Then we learn about something like MBTI or other typing systems. We learn that people's brains are structured as to interpret information differently through different cognitive processes, and it all starts to make sense. Suddenly, rather than seeing an action as being stupid and irrational, we see it as "oh, he's much more of an intuitive-feeling type, and consequently, it's the emphasis on (internal values/group cohesion) that's informing his decision-making, rather than hard analytical logic. That makes sense".
The problem with miscommunication comes when your assumption is that through this process, we're making value judgments about the person. This is particularly the problem with the English language (and perhaps, all languages in general), as while we NT'ers are very good at understanding shades of meaning, we find the shades of meaning more important than the shades of emotional impact. So where I would think "oh, he's being very NF right now", meaning more "he's acting in a way that is consistent in what I know to be characteristics of the NF type, and consequently these actions can be interpreted as such to maintain a logical cohesion", you may interpret it as "oh, this guy thinks I'm just a box, a type, a stereotype. He has no interest in understanding me as an individual".
Which often in reality, isn't very true. The NT type, particularly in my own understanding of it, generally has only three categorizations of people they interact with - "trusted", which includes friends, family and other respected people; "neutral", which includes unknown people and public figures (as we only understand their actions, and cannot understand them as people with such a small set of information - thus, why there's a lot of iconoclasm and little hero-worship); and "untrustworthy", which most people would qualify as enemies; however, we have a tendency to think there is an explanation for their actions beyond personal dislike (which can often be incorrect).
Once in the "trusted" category, there's very little one can do to remove themselves from it beyond out and out blatant betrayal. In most situations, you'll get the benefit of the doubt, and if we're angry at you, we'll still get over it. You're not going to descend in our estimation - at worst, we'll be annoyed with you for a little while. That doesn't mean we don't like you, or like you less than we did before.
So if we make an observation about you, please, please do not interpret it as indicating that we think any less of you, or are dehumanizing you, or trying to fit you into some sort of a box. We're just trying to make sense of actions whose rationale does not seem immediately apparent. We want to know you better, understand who you are, and understand what motivates you.
I understand that this can be somewhat uncomfortable, because we're not inclined to settle for the surface explanation. Just keep in mind that we're not judging, we're learning.
Too often the point is made that we're the ones in the wrong, and we need to change our actions. I do not disagree that we need to be more conscientious of how our words impact people; hell, everyone could use that lesson. That being said, please do not make the assumption that we intend any sort of ill-will in the things that we say. As painful as insensitivity can be to you, so is frustration for us. A little tolerance and understanding can help everyone in this position.