In the old days, you often got a letter of rejection after an interview, and I started collecting them. That turned it around into a fun game. And after a while, I realized that several of them were based on a common template.

There must be some old HR book out there with an example rejection letter that many corporate HR departments used. It was calculated to let you down easy, to avoid making you mad and miserable.

Point being, it was always rare that you would get actionable feedback from an interview, because it was always risky. Now it is just rare to the point of non-existent.