Yes. Bananas is just pissed that Sarah and Jordan beat him at his own game. I have no doubt that he would have thrown them in if he had won that last challenge, and he would be the one saying it was all just a game.
He has no real income outside of challenges, so he comes in and expects the big paycheck, to the point where he expects people to be okay with just handing it to him. He can't separate the game from reality because he's made the game his job, which only works if you win.
It being an "act" doesn't really excuse him treating Sarah, his supposed good friend, the way he did. You can put on a personality without alienating, insulting, and being a monstrous dick to people you actually care about. Which is why I don't believe he's such a good person in reality.