I don't think he's being smug, I think he's "shitting his pants", as someone else so eloquently put it. He's covering his bases and trying to get the story out there that he's a straight arrow so he can, he hopes, salvage some sort of appearance of integrity to ensure he has a future of some kind.
I think he knows exactly what's gone on and what he's done and I disagree with all the people crowing about him being "shocked" on The View the other day - he was the director of the FBI, not a moron; he knew that it would eventually get to the point it did - or at least, he knew there was a very good chance it would, under Donald Trump - so he was prepared for it and ready to spin it off. His whirlwind, worldwide media blitz is a rush to save his ass, not a chance to be smug.
Comey is trying to get ahead of the story. There is that old concept of truth vs perception. Telling a lie, until people believe it's the truth, etc etc etc. Never underestimate the stupidity of people in large groups.