How are the students interests, abilities, and future career paths served by taking bad courses from professors with no interest in teaching, because they're too busy giving interviews / doing research? Perhaps Yale should let the students balance all factors, including what their peers thought of the class. It's not as if the website casts a spell on their feeble brains and removes any consideration of critical thought. Is it Yale's duty to protect its customers from truths they "cannot handle"? Would you say Yale should ban Amazon book rankings, in case the student doesn't know how to handle a one-star ranking and decides to burn the book?

Many rankings are indeed subjective (books.. classes.. movies) - in fact that's rather the point: to render ones opinion.