I would suggest perhaps perusing this thread and others on the same theme on this forum recently, especially the discussion of random variation in small samples (i.e. the number of people in a given class interested in a particular field). The idea of noise and statistical power is a useful one and
What you said. As someone who switched from Rads --> PMR, I can guarantee that Psych is not and never will be like Rads for countless reasons. While Rads has had some rough times, the main reason Rads has become less competitive is because it is a grueling specialty that made bank and it's been cut so many times it's not even funny, to the point that having to go through 6+ years of grueling training for the current starting salaries is sometimes hard to stomach, not to mention that the decreased reimbursements have caused many not to retire, leading to less jobs. Psych is in no way comparable to Rads, so please let's not be silly. If someone loves psych, great apply to it. Trying to make it "better" than what is it or how competitive a field is to make one feel better is outright absurd. Second, as you point out, competitiveness has to be gauged appropriately. "More people in my class interested in x, y, or z" is not a statistical method to anything, and as a future physician, that poster seems clueless. You certainly don't gauge a field's competitiveness by how many people in one's class are interested in the field.
Second overapplying is a common current phenomenon that occurs across fields, so people applying to more spots does not mean it's more competitive, it means people are more paranoid of not matching because of INCREASED APPLICANTS. If I were to simply go by my program's applications, we have close to 1000 applications for less than 6 spots.
Third, suggesting that someone believes that "Psych is more competitive than FM, PMR, IM in the next match" - again is silly. Psych is one of the easiest fields to match into. Nothing wrong with that, it's just the way it is. It's far easier to match into Psych than IM or PMR. With PMR in particular, given that there are less than 400 spots nationwide, and that we fill consistently with pretty much no spots available throughout the country for multiple years, I can safely say that it will be far easier to match into Psych than PMR, and also IM. IM is far more competitive than what that poster is making it out to be, particularly at top programs.
The reality is that the competitiveness of fields has remained relatively stable for a longgggg time, including Psych. Non-match paranoia is rampant and people are applying to more spots across the board. Rads has had a rough bumpy road for a few years, but let's not become delusional here.
Psych is a fine and necessary specialty, but again, pretending that it's somehow become the end all be all makes no sense and it makes people who make such statement look bad.