> The latent streak of puritanism, maybe
The main problem is that addiction kind of goes around people's interests and their better judgement.
Normally I agree, we don't need to be making 'moral' decisions for people. If they want to do something 'sinful' - like gambling - have at it.
But the people who promote gambling have lots of money. And gambling is basically smoking. So, it gets hairy. They can lie, they can cheat, and they can manipulate people's minds, tricking them into doing something bad for them. And then the addiction does the rest.
Absolutely addiction does; so we're going to ban alcohol (and weed), and then maybe move onto video games and books and and and and?
Prohibition has generally been a lot less effective than regulation. The problem in the US, in my view, is much more the utterly-gutted effectiveness of the regulatory state than it is the existence of legal gambling.