Taxes and government is completely different thing.
Without tax collections, government offices won't work, so it's not completely different thing.
If we follow logic allowing gambling = state treasury being filled by taxes = more money, then why not allow drugs.
Do you think its easy to allow illegal drugs? Allowing such things to be legal is not all about tax, it's mainly the health of those people who consume such thing and then the cons of having it on people. Or is it even possible to regulate illegal drugs being legal? I don't think so.
By the amount of money involved there, that would be a huge addition to country budget.
Yeah, and be listed on FATF's money laundering list so foreign investors will avoid that specific country and be only dependent by its borders.
It is not correct to ban everything one person don't likes or have different opinion.
Banning things in any country does not fall from one or two person's ideas only, it consist of lots of decision and voting depends on what kind of government a country has (senate, congress, prime minister, president, etc.) not unless its dictatorship way.
In case of gambling, it's business, jobs, tourism and money. Casinos have one of a kind resorts, hiring lots of staff, and of course tax from the business and from the staffs. Macau is one of the example of this, 50% of its GDP came from gaming/gambling industry.