I would not be so hasty in listing which countries have made gambling legal or illegal. Because the truth is, in every single country on earth, gambling takes place. Whether in a grey area or in a illegal black area of the law, it still happens.
Lets take a look at Japan, as an example:
Japan officially declared gambling as immoral and illegal, however despite all that the Japanese gamble. How? They simply do not gamble for "money". But rather "tokens" which can be exchanged for something worth a lot of money. For example gold. And that later gets exchanged for actual money. They do this in front of the authorities and everyone knows that the gambling laws are just a big sham that do not work.
Well it's true, that it's no secret that gambling is actually everywhere in the world, even though it's prohibited.
Although some countries prohibit gambling activities, in fact gambling still occurs massively throughout the world.
I think that gambling ban regulations are ultimately considered just a formality in every country.
We know, in reality the rules will lose and submit if there is a lot of money flowing there.
In every country that prohibits gambling, even though the government and authorities are aware of and aware of the gambling activity.
The prohibition on gambling would barely touch the powerful and wealthy groups of people to bribe.