I think it's better for people to think it that way like they are commiting sin if they are doing the act of gambling because we know that it doesn't do anything good.
Religion just want to control us. However, there is a better side on that, when they think of gambling as sin, they are preventing us from doing it.
Even without a religion, for the sake of having a good life and for the sake of morality, we should not gamble too much. Doing it too much is the only thing that makes it dangerous to us, and too much of it will pull us back to poverty no matter how hard we try to gain money.
This depend on the person on how they will carry himself. He can be pulled back to poverty even without participating in gambling if he will not discipline himself. Failed people always look for something to blame and this time they put blame on gambling which have nothing to do about their decision of betting and losing his all assets. Gambling never thing, people do, gambling never make decision for people if they will bet or not, people do. So all in all it is people's fault why they go back to poverty.