... Typology merely provided a language to more clearly express things. It didn't create the tension.
If a person had a uncomfortablness with Feelers before learning typology, then can one really say typology created the prejudice or is it just making a previous prejudice more valid and tangible? I say it's building on something that pre-exists it.
Good post. And finding that language validates those experiences and inclinations. The problem with Typology is that it takes those personal, experience based tensions and projects them onto humanity. For the INFP who feels tension with Ts or Ss in a personal context, it isn't a guarantee that the same tension will be created when interacting with others who have been labeled similarly. It might increase the chance of duplication slightly, but in some cases not. The labels are extended based on personal interactions to determine things they are not designed to determine. For my own experience interacting long-term and personally with four people who tested INTP, I can guarantee that although there are some threads that connect them, the interpersonal dynamics are completely different. And I also realize that my personal experience does not determine the larger picture, but it serves as a counterexample to assumed consistency. There is also the issue of confirmation bias where whatever is expected in others based on their label is what is perceived. My primary point is that typeism can inhibit communication by having to sort through a great mass of personal projections between people.
It can also distort a sense of self, when people impose these categories onto self. That is part of the problem with MBTI as a measurement tool and which is explored in the book mentioned in the OP. You can take any definition if it is broad enough and the majority of people can identify with it. It is the same way that Astrology is self validating. In that system I am a Capricorn which are apparently described as methodical. Well, in a certain way I am, but in another way not so much. Still, if I embrace that system and internalize that concept of self, it could cause me to become more methodical because that's "who I am". If I were a Gemini, then I would remember how as a teenager I defined the complexities of my personality as having two distinct sides, each of which I named. If I were a Taurus, then i would remember times I was driven and passionate. By finding a certain hook in the definition that has personal relevance, I then internalize the whole of it and reshape myself to become it. This doesn't have to be a conscious process.
Also, because Typology does not have a cultural context, a person can express prejudicial thinking and form elitist views without the negative labels associated with sexism and racism. It is easy to forget that people who embrace sexism and racism consider themselves to be thinking accurately and see proof for their position. In the last century there were even example of "scientific" evidence to support racist and sexist views, plus a long history of others, some brilliant minds, who made the same assumptions. It can feel intellectually safe to be able to dismiss racism and sexism, but to see typeism in a different light, although it has even less of a "foundation". A person can have the satisfaction of dismissing others who are labeled differently and consider themselves to have special insight rather than non-critical thought processes.