Matthew Yglesias debunks a myth without establishing that anyone believes it.
Clue to Matt: No one believes it.
This is one of those glaring examples of the attitude of superiority leading to missing humor and subtlety. You may think you're smart, but it's not smart to assume other people aren't smart too. I recommend a working assumption that other people are smart, and when you think you're reading something ridiculously stupid, go through the exercise of reading it with the thought that the writer is wonderfully clever. This is especially important when you are reading something concise/elliptical. Look at every word. Think before you mock.