it's crazy to see that mentioned so non-chalantly. my expectation is that the teacher, when they grade, is meant to be impartial, as if they were doing nothing more than taking a measurement of the student's work, you could say (this is why, i believe, we value standardized tests in some settings, even though they are worse in other aspects). it's the student who is responsible for the grade. a teacher not being allowed to give F's to everyone suggests a corruption of the system to me.
can you share more? what pressures teachers not to do this, for example?
Mostly though I was just chuckling in my head about an old curmudgeonly professor of mine who was literally retiring at the end of that semester. We were all actually quite scared he would go out with a bang given his disdain for us. We weren't like 100% Fs or anything, but I think it was obvious we thought the material was pretty phooey and the lectures interminable.
But why would this automatically cause the teacher to be the one to retire?
Are there documents or books on this? This system seems so alien to me. And yet it does seem to produce some amount of competent graduates who can -eg- launch a spacecraft into lunar orbit.