1) I don’t think most students understand how difficult it is to give bad grades. With good papers you get the joy of offering simple encouragement and ideas for taking the work further. Who doesn’t like grading good papers? But with bad papers you spend forever trying to articulate not only what went wrong but how one might rearrange things to climb out of the morass that you’re confronting; it’s not easy to disentangle a train wreck, much less in terms that the student will understand. It takes a long time to grade bad papers and a lot of mental energy.
This is all compounded by the tacit understanding that students who get good grades won’t question them; it’s the students who get bad grades who will look for a way out, will try to blame it on you (as in the case of my student this fall, who followed a comment about the bad grade on her paper with a question about my teaching qualifications), or will, in even the best circumstances, rely on you to show them the long road to improvement.
I worry when a professor has a reputation for easy grading, because all too often it means that he is overworked or tired of his job. I don’t think he is doing his students any favors by giving them good grades, although I can easily understand that professors eventually get tired of the struggle over grades (which are not the focus of one’s teaching anyway!); he may give up the grade struggle, hand out acceptable grades, and then try to motivate students to improve through extensive comments on their work. But that does make it a lot more difficult for those professors who are still trying to work within the traditional understanding of grading, who then appear to be “mean” graders.
2 ) My students are used to getting bad grades. They come in with stories about the chemistry exam in which half of the class got a C. But if I handed out C’s to half the students in my class, I can guarantee that I’d have a faculty advisor chatting with me within a week’s time. “Bad” grades are acceptable in the sciences, but not in the humanities. You can guess how I feel about that.