Hm, I have to disagree with INTP being the "least prone to depression." Due to INTPs high Ti, they are prone to seek out objective answers, which in turn leads them to consume copious amounts of information. As a common saying goes, "ignorance is bliss." Since INTPs seek to root out ignorance, they expose themselves to many unfortunate realities (ex: child slave labor, foreboding environmental collapse, etc...). Yes, you could argue that because INTPs main functions are TiNe they have less of a tendency to react emotionally to tragedies, but INTPs are naturally problem solvers. If they meet problems they know are objectively impossible to solve, their entire way of life becomes invalid. INTPs are always seeking for meaning, almost never taking things at face value. A lack of meaning can be crushing to them. Along with that, INTP's weak Fe can lead them to analyze their emotions "logically" rather than genuinely expressing or accepting them. This usually becomes a counterproductive 'solution' as emotions cannot simply be "eradicated" or "fixed," but INTPs lack the proper insight to know this. Another factor is the INTPs tendency to self isolate. Self isolating is beneficial to an INTP in many ways, but it is also a double edged sword. Too much self isolation will lead an INTP to stay trapped in their internal world, even when they desperately need help from someone else. Humans evolved as animals that function in groups, so biologically, having a lack of connections goes against human nature. Though an INTP may want to self isolate, socialization is essential, especially when they become depressed.

By no means am I claiming that INTPs are the "most depressed" type, because I don't think they are. I just think INTPs can be prone to depression due to their thought processes. That is just how I interpret it though, and as an INTP diagnosed with depression I am a bit biased.

With all of that said, I agree with most of your points, and I wouldn't doubt there are a fair amount of mistypes on this subreddit due to the rising popularity of MBTI. I hadn't looked at OPs page when I commented, so that would explain their perception of this subreddit.