I call that the “Mussolini Pose.” Obama used it a lot.
He's carefully honed a lot of his mannerisms for effect. So, he couldn't have been aware that his chin up, soaking the crowd approval look, wasn't Mussolini-like.
So, like you, I've wondered why he kept on doing it? I don't think that even for the many who adored the Won, that it was a crowd-pleaser. Maybe he couldn't help himself? Or, maybe he thought he was destined for greater things?