That’s a great point. I think a lot of jobs get hundreds of applications, but if you’ve interviewed, and sometimes more than once, they ought to let you know they made another choice, just so you’re not left feeling like you’re not worth dog crap to them.
My feeling is that anyone who has been interviewed, unless they withdrew from the process on their own, should receive some feedback about someone else was hired or reasons... I expect part of the fear for hiring managers, is that they will be taken to court for some discrimination issue, so they might feel that the less said, the safer/better.
When I was involved in hiring, which was over about a 30-year time span, I would always communicate with those who interviewed to let them know that the position was filled, if they were not selected.