I've heard a number of stories in the UK, U.S. and Australia where the University employs the professor for research and not teaching. The Professor hates teaching and treats it like an inconvenience. Then students are screwed over.
The universities that pay their salaries and the students that pay the universities should demand more from their professors. If students get poor grades for not understanding the assignment then it is only fair that bad professors get a poor review for not understanding the assignment.