[IkmoIkmo]

But the article ends with a student expressing disbelief as he did decent work and getting an F before the class even ends, and the professor acknowledging that some students were fine, but that he exercised collective punishment because it was his only instrument.

That seems pretty clear cut to me, definitely a bad move. It can't be justified, solves no problems and punishes innocent students.

I'd understand why he'd fail some of his students, and I can also imagine situations where it's tricky to pinpoint and isolate the unwilling students from his class, and if made out to be a clown day in day out, lacking the proper instruments, management backing and (understandably) mental fortitude, that you'd leave the school at some point.

But how that translates to giving an F to an entire class, including students who bore no responsibility and were as powerless to keep the class going the right way as he was, is beyond me.