I've been on the receiving end of "thoughtful" rejection letters. Some have been helpful, but some really served to cement the subjectivity of the whole thing.
The "funniest" one is one where I in fact knew the person who got the job. I received a nice and long rejection letter explaining all the points they found off for me. I was too aloof during the interview process itself (thinking I was a good fit), and many of the points mentioned were not wrong. But I knew for a fact that I was better than the person who got the job on all the mentioned points[0]! There was one thing not mentioned, a pure "culture fit" component[1]. Pretty sure that was a decisive factor, but not mentioned.
It just felt like something where, if I didn't have the full context, I would have really bogged myself down from "wrong" feedback. And when feedback can involve innate parts of one's personality, from people who have already decided to not work with you, it can be painful.
[0]: I worked closely with this person for many years. I do not have ill will towards them, the skill gap I'm mentioning was purely a "years of experience" thing IMO
[1]: for the curious: the place hired loads of people in a certain community, of which ~all of them were from the British Isles. I am not.