"Too much traffic"
There was an influential article in the 1980s called "Grammar, Grammars, and the Teaching of Grammar" that made a strong case against teaching grammar. Fish of all people should know that grammar goes out of style, Anglo-Saxon permits double negatives, and today's grammar was invented in 1758 in a London coffee house for the express purpose of persecuting the Irish. Also, grad students who try to write well have been warned against being journalistic hacks since 1967. Lynne Cheney. Ha. And the public editor bashes Cintra Wilson? Ha. Last Fish piece I ever read.
I agree with Professor Fish. As an English Literature major, I have experienced this deplorable situation first hand. The irony is that those same teachers who renege on their responsibility to teach grammar will still hold their students up to the traditional standards while grading their compositions. The most irresponsible of all are the writing teachers. I have taken several college level writing classes, and every one of the teachers began the class with a proclamation that "writing cannot be taught" as if writing involved no technical skills, only creativity!