you are mislead
In my experience, INFPs are the most "typologically confused" - they test INTP one morning, then ESFJ the next.
Anyway, I've noticed that people who discover Myers Briggs often do so through a search to understand themselves. And frequently, this search is triggered by a perception that there is something abnormal about them. So that's why a lot of Myers Briggs boards tend to have high number of Ns (Ns being in the minority in the general populace, and frequently treated as an albatross by a lot of social circles), and then there are people who have mental issues who are attracted to Myers Briggs (people with mental issues also have trouble fitting in, you see). And of course, Myers Briggs is a big relief to Ns with mental issues. So I see a lot of people with mental issues using a particular type as an explanation of their abnormal mental states i.e., "I'm not schizoid bipolar, I'm just an artistic INFP, lol", or "INFJs are the rarest types, no wonder everyone in school always thought I was a mental case". Some people mistype themselves because they read some crude type-explanation and think "It says here than INTJs tend to be cantankerous assholes. Hey, I'm a cantankerous asshole. I must be an INTJ!"
And thus you get all these people causing general type confusion.
By the way, y'all need to stop with the "I'm an INFJ, and even though I'm a J, my desk is messy!!!" stuff.
A LOT of xNxJs tend to have messy desks, even though they are Js. That's because they are also Ns, and as such, often spend too much time in their head and ignore their physical surroundings, resulting in general disarray. It's not some mystery INFJ-specific trait.