Billionaires are annoying in gambling; they are powerful, and they don't want to be messed up, Lee thinks that he's been abused and misled, and he has the money and battery of lawyers to get back to casinos, so he is charging the casino.
If you're an average player and you are charged at a casino using these reasons, the casino will just ignore you, but it's different if you're a billionaire.

This is a lost case, unless he uses his influence and money to win it. There were loopholes in his charges, so the casino can easily ask for dismissal of the case if his status does not threaten them.