@skdh@nerdculture.de
I thought that reference letters were an indicator that the candidate had the correct habitus
[cf. Wolf Wagner, "Uni-Angst und Uni-Bluff"] for the exclusive academic circle into which they were to be admitted,
i.e., to make sure that the candidate is not only technically qualified, but also knows the jargon and knows which fork to use.

When I studied physics in the last millennium, this was about the „Greiner Mafia“ in theoretical physics.
Nowadays, it's probably about the proper use of pronouns instead of forks, i.e., proper use of "inclusive" language as exclusionary criterion.