He's different with the home cooks in MasterChef than with professional cooks on shows like Hell's Kitchen and refurbished restaurant shows. He'll get a little short with the home cooks toward the end of the season, but considering they are usually dumb mistakes at that point, then... I'd get a bit short too. He's definitely different with the kid's shows he runs.
He's also mellowed from the beginning shows of Hell's Kitchen. His behavior and the way he spoke to people was waayyy out of line early on.
And let's not forget about Joe Bastianich. He doesn't yell, but some of the things he says are extremely cutting and just downright rude to home cooks. You might not like someone's food, but you don't have to be horribly brutal about it.