I had a professor from hell too and while I got good in his class it was a really bad and unnecessary experience. He was the kind of person that you'd need to ask a clarifying question and he wouldn't want to listen, he'd send you back to reread syllabus and other course documentation without wanting to listen to the full question. Whenever people were stressed out and confused he'd slightly smirk, the only time he'd show any expression on his face.

This professor was tough, wasn't teaching too well at all and often would route you to the materials without giving any further explanation. This was undergrad and as an experience it was really unnecessary in my opinion other than to show you that in life you'd run into arseholes and you'll have to deal with it.

I don't know the professor in this case but my understanding was that students didn't want him fired, they just wanted to clarify exam questions and/or the exam questions style, clarify materials for exams and all which seems quite reasoning to me. I read some vulgar spins in newspapers that students don't want to do their work, they're lazy and entitled and so on. That is most likely oversimplification