A Simple Desultory Philippic is a hilarious parody of the 60's and, more specifically, of Bob Dylan and his fans. Of this song, Paul Simon said, "This is, of course, a take-off, a take-on, a private joke, but no joke is all that private or any less serious for being a joke."
Dylan and his fans are most scathingly mocked in the middle section when Simon sings, in an obvious Dylan-esq whine, about a man who's "so unhip, when you say 'Dylan' he thinks you're talking about Dylan Thomas, whoever he was. The man ain't got no culture. But it's alright, Ma, everybody must get stoned!"
I think Simon keeps the parody at a humorous, as opposed to a personal or hurtful, level when he includes his own work in the list of things that he's sick of. "Been Roy Halee'd and Art Garfunkel'd."
Listen to the original version for alternate lyrics and a more mockingly authentic Dylan guitar riff.