Well, they are banning it for the sake of protecting their belief, as it was against their religion. For me, it was not the loss of the government, as in fact, they managed to stay firm even without gambling. Besides, they have a valid reason for doing it, and they value their belief more than money.

Don't get too absorbed in why some countries ban gambling. Many people lose opportunities for something more important. If gambling is allowed in your country, then you're lucky. But they never question those countries that ban gambling; they also have the choice.