"I stopped expecting angels to make sense a long time ago."

That's actually mostly a lie; he never believed in them, and then Cas was kind of terrifying and suspicious and mildly threatening right out of the gate, so... So that's a never on expecting angels to make sense. He never thought that would happen.

"I don't know how any of this works. What I do know is that angels are shady sons of bitches, and they can find a way to justify whatever horrible crap they decided to do now."

Unfortunately, that includes Cas.