He's a 21 year old notorious hothead, so I'm not really surprised. I also don't really care. It was kinda bad judgment in the heat of the moment, but the bad judgment was purely in making a gesture that would obviously be picked up by the cameras rather than talking trash like these guys do every second that they're on the field (Brady included). In other words, it's a minor slip up that doesn't matter and shouldn't move the needle at all. I don't want to watch the type of football where we expect guys not to get competitive and mad at each other. Not surprised that the media is blowing up a non-story, though.
I also thought he handled the repeated questions about it in the postgame pretty well. I'm no Manziel fan, but I actually like him a little more after last night.