That's the rational way of looking at it, but if there's one thing people will very seldom admit is being irrational about things that matter to them. Specially beliefs that align with their desires. Wish fulfillment is one of the big factors in people getting personality theory wrong, not only in Socionics. A lot of people are looking for confirmation that they are who/how they believe/want themselves to be, not discovering more about themselves, because that can break the illusion.
Socionics/MBTI also poses as a guide to life for them, a way to navigate a world that scares/eludes them, so it comforts them to believe that they can easily spot people to match them in every area of life, hence so many threads about people of a certain type not behaving like they "should" in relation to the OPs. Not every lid will fit every pot even if they are from the same brand