I could not agree more with Mr. Crowder and Mr. Rojstaczer. And they don't. Thinking is hard.
Opinion is easy.
Failing students for providing opinion instead of insight is perhaps too painful for the faculty. It would mean a lot of explanations to angry administration and parents. But we've set up the system to reward affection, and the easiest way for a professor to ensure job security is to be well-liked, not tough and filled with intellectual integrity. I have had a faculty member in my department tell me that even in this small liberal arts college where teaching is stressed above nearly all else, classroom time is a chore that interferes with his research interests. But I can't really say that more of the blame belongs to the faculty than to the students.