I think too many on here are too pro-mario or anti-mario to see the wood for the trees.
I'm certainly not his biggest fan, and to be honest think he is more trouble than he is worth, but we need to look at this incident in a bit more isolation to judge it.
He made a bad tackle on Sinclair, which player hasn't made a bad challenge in training? If we were all watching training (which sounds like it could actually be possible to do) and was sinclair with the ball and mario not bother to challenge him, everyone would be screaming 'lazy,' 'doesn't care,' 'not interested' etc.
He made a challenge, which was probably not the best, but which striker can tackle?
Mancini has had a go at him, we don't know if this was a reasonable and justified 'go' or not, and mario has gesticulated at him. How many times have we seen mancini do that to him and othe players? Does he have a case to argue when someone does it back to him?
From all of the pictures it seems than mancini was the aggressor, yet mario gets all the blame, because he did what? Maybe threw his arms in the air and said shut up, maybe more, but nobody on here knows so how can anyone be so critical without knowing the facts?
This may seem very anti-mancini and pro-mario but it isn't meant to be as I'm of the opposite belief.
Lets just wait for some more facts before hanging anyone.