The issue isn’t INFJs, because you’ll probably find the same behaviors in other mbti subreddits for the other 15 types
The issue is that mbti is presented as a personality map the same way astrology is (even called astrology for ...idk it was astrology for some group? Psych majors?). It’s not
MBTI is really a map of how you think or process information, and a lot of it isn’t straightforward so it gets lost in translation. Everyone has the capacity to think rationally, have appropriate feelings, be connected to their 5 senses and create patterns from input. People just have some skills more developed than others, and MBTI type is liable to change if someone really makes giant changes in how they develop and utilize skills. Feeling types think, thinking types have feelings. perceiving types aren’t all boho hippies who smoke weed and get into woo woo mystical bullshit. Judging types aren’t all anal perfectionists with 100 to-do lists who get everywhere 5 minutes early, or at worst German late. It becomes a stereotype if you make being a STEM or humanities major your entire personality.
The test itself is misleading, because it seems like a personality test. Its really just easier to type that way than to try to know your cognitive stack...manually? Just by saying “oh I think and it’s directed inwards so I’m a Ti dominant type”. The mistyping would be so much worse because people glamorize types by their stereotypes. You’re more liable to make yourself what you want to be if it was that plainly direct. Things like being extroverted (not outgoing. Also ambivert isn’t a thing. You believe in introvert/extrovert or you don’t. Another rant another time) or needing lists (Judging) are just there to type without being stupidly obvious. Knowing whether your extroverted primary or auxiliary function is P (sensing/intuiting) or Judging (thinking/feeling), and whether your primary function is I/E is there to organize your cognitive stack. The entirety of the stack makes the type.
Example: An infj’s extroverted function is feeling (j), and their primary function is introverted (first letter). That gives us primary introverted intuition, auxiliary extroverted feeling. Then the next two functions follow in terms of I/E order, and “flip” or “mirror” in a way? Because feeing is extroverted, thinking is introverted and is tertiary. Intuition is introverted and dominant, so sensing is extroverted and very underdeveloped. Sensing is right at the bottom.
Any kind of personality you glean from that is basically how you process and interact with your world. Which says some things, but hardly enough to really get an entire personality from. It says how you process your world, not how you think or what the inside of your mind is like. It doesn’t say what you’re good or bad at, what your sense of humor is like. People with the same type could be total opposites in terms of personality.
The stereotyping happens because people don’t use it right. It was originally intended in a clinical framework and possibly also io psych/having multiple people work together/harmonize. Mini rant/essay over. Might delete tomorrow