Betting on your team to win is not necessarily good. You may go all out to win a game, say overwork your closer, and it could cost you games down the road. Also what about games where Rose didn't bet? Was that a signal that he was going to throw the game?
You obviously don’t know the attitude Rose brought to the game. Winning was the only thing which mattered in any game of which he was a part.
Rose could no more throw a game than the Pope could mug a Nun.