And you can compare this article against the entire book that he published about the left's flaws this year. On one hand we've got an article critical of the right that finds the need to smuggle criticisms of the left in constantly and on the other hand we have a complete manuscript. You tell me where Williams is focusing his attention.
But you're also making this point about all signatories being hypocrites because you seemingly have a big bone to pick with the amount of blame Thomas Chatterton Williams portions to each side.
Williams is a public intellectual. What goes on in his mind is of much less importance to public discourse than what he writes.
Let me be clear. I believe that Williams is a hypocrite and I believe that the large majority of the signatories on the harpers letter are hypocrites. I mention him specifically because he was one of the people who actually wrote a lot of its text rather than just signing it, which makes him of particular interest for this discussion.