The question is already biased because it assumes that LeBron does cheat ("if he is such a good player, why does he cheat") instead of asking "do you think LeBron cheats?" or something like that. I'm pretty far from being a LeBron fan, I don't like his attitude at all, but I do think he is easily the best player in the NBA right now.
As for his practice of "fake fouls" and "flagrant fouls", that's neither something new nor exclusive to LeBron and the Heat. Even Jordan resorted to a bit of that in his prime. That's part of the game.