In many countries where gambling is a taboo - and people do not gamble because its not legal and its considered as a sin.
The people there can do online gambling and satisfy themselves. However - those people have a thought behind their mind if they are doing the right thing or not.
Gambling can be subjective. Those countries where gambling is a taboo has a very simple definition of gambling. Don't they realize that in real life we also gamble or take risks? Gambling is a form of entertainment, it only becomes a sin because most people get addicted to it with the mindset of it can make them rich in short amount of time, which only happens to very few people that are lucky. Gambling is a business to entertain people, they did not promise some returns.
Despite of illegalities of gambling in some countries, i believe gamblers do not settle on that and won't gamble at all. They will always have the time to gamble, it's just that they should be extra careful not to be caught by the government officials. Maybe that's how they see it as a sin, contradicting the laws of the government. But in real life, people somehow need to gamble too because its just a form of entertainment but in a business way. And you need funds for you to be able to gamble, whether you win or lose in the end.