Nah. Mancini may have appeared to make "too big a case of this" but this is a clear case of Mancini having it up to his eyeballs with Balotelli.
Remember, Mancini claimed that he didn't have any problems with Balo when HE was the coach, while Mou was putting the player in the freezer and the media was making a mountain of it.
Smart Alec Mancini thought he was "special" to Balo and that Balo would look up to him and be a good boy, so he signed the young Jedi at City. We all know of what happened with Balo at City during the course of the season, and Mancini is now already - obviously - a pretty frustrated coach. This incident at the Galaxy game only shows Mancini's patience with Balo is now wearing very thin. And every "little" transgression by this "Italy's future megastar" is going to trigger off Mancini (or any coach in his shoes).
Look at the video. See how Balo talks back at Mancini and then walks away while the coach was still talking. Anyone would be triple pissed to be in Mancini's position. You don't talk back and walk away while I, the coach, the manager who manages the team, YOUR manager is still talking to you. You just do not do that. The body language is obvious and it's happened many times before - Balotelli respects NO ONE. He has said it before - that he thiks only Messi is "just a little bit" better than him. The small fart thinks he the second best in the wiorld.