certain ass face directors

Indeed, this is an interesting subject matter.
Personally, i think you have ALL made some good and valid points
The point that a director simply hasn't got time to call 50 people back and "let them know"is valid and true.
Perhaps thefore the person who has auditioned should call back to see how she/he has got on. I mean, if this person is really interested and passionate to get a role,a simplea phone call on their behalf is not too much of an effort is it?.
However, what if there weren't 50 people. I recall someone being somewhat suprised that this director had even got 50 people to audition. What if there were only 5 people who were unsucessfull. Well then surely it wouldn't be too much of an ask then, for the directorto let those people know.

Personally, i think it's up to YOU the ACTOR to find out for yourself why you may or may not have been cast.

I am a newbie to this amateur world and do you know what?, I see already so much bickering, and complaining and moaning amongst some of the good points and useful advice thay has been made. Be grateful that you have such a vibrant community and encorage actors to be PRO-active in their approach to what we are doing.