No, no, I know--I have to stop or you just won't be able to stand the excitement. Anyway, Younotsneaky, one of the world's awesomest economics bloggers, does it with math. Meanwhile, in the comments to the Kathy G. post, Tyler Cowen says what I said, better, in one paragraph:
You either think that the demand curve for labor slopes downward at the relevant margin or not. If you don’t think it does, you need to argue for that directly. Arguing that the labor market is not perfectly competitive—while true—does not get you there. And if you admit the demand curve slopes downward you are already very close to Kevin Murphy’s point of view.