Liberal-hating Liberal disease?

The great pundit-god Yglesias observes:

[I]n today's offering [Thomas Friedman] is still playing what Greg Sargent has dubbed the "conditional shuffle" responding to Bush's proposals by listing scenarios under which he could support them rather than facing the reality that Bush isn't going to do any of these things. The trouble, obviously, is that were Friedman to acknowledge that Bush won't, say, hold a regional peace conference, he'd have to admit that the right thing to do in Iraq is withdraw.

And, of course, once you don the Moustache of Understanding you'll realize that in order to be a Serious Person it's important that you never agree with liberals.

It's easy for me - as a liberal on foreign policy - to believe that Friedman is undergoing these contortions because he is emotionally averse to adopting the left-wing opinion on matters of foreign policy but surely people who don't hold my left-wing foreign policy position won't find this kind of explanation terribly compelling. I'm curious how they explain this kind of rhetorical two-stepping on the part of Friedman.