http://ftw.usatoday.com/2016/02/cam-newton-critcism
Good read. You might look at this, not just as criticism of Cam Newton, but all players including Griz and Cats. We want these guys to play with emotion and clearly Cam was/does. Why then do we criticize them for being too emotional causing them to react in ways "a player should not react." This isn't golf where constant composure is a required element of the game both in decorum and performance. This is football. You feel it when you play it. Cam Newton feels the highest highs or the lowest lows when he plays. I'm not sure we can fault him for that.
The Panthers didn't lose because of Cam Newton not diving for a fumble. They lost because the OL couldn't block the tremendous pass rush Denver brought and the dropped balls by receivers. Those plays were repeated over and over again throughout the game.
As far as him getting up from the press conference after the game, Trent Dilfer said it best. Less is more. Sometimes not saying anything is better than saying something you'll later regret. I agree. If he'd have blamed his OL and receivers (deservedly so) that would have been a far greater sin.