Why bring religion to gambling at first place ? Let's just see it as a person who is winning money from gambling.
I believe because religion typically teaches that gambling is taboo or unethical to do due to greediness while the subject is a preacher of this teaching which show hypocrisy.
I don't agree to ban the user directly from gambling but we can restrict a gambler who is always winning money.
After a certain win if the gambler keeps winning then casino owners can impose a restriction on him because that's how they can keep the business running.
Is there any difference between banning to restricting? Both of this action has same effect to gambler since they can’t use the casino anymore to gamble. I believe limiting is the right term if you are pertaining to decreasing the amount of bet which players can put on his bets.