I have friends who got rejected by FAANG companies and got precise feedback as to why they didn’t get hired, specifically from the interviews.

And recently, I’ve been rejected by multiple companies in the interview process and all of them said why they rejected me.

If I had to guess, most of the time it’s that telling people why they didn’t even get an interview is time consuming and not all that productive. But telling people why they didn’t get hired following interviews makes sense since the candidate made a substantial effort to get there.