This seems like a bit of a political issue instead of ethical issue if you ask me. Why? Because "banning" something, or making it illegal, is the work of lawmakers, hence the politicians. So if a politician, or all of them, get together and make gambling illegal in a country, they are making a political stance. I believe that a thing that doesn't hurt others, should be allowed, that is the liberal approach, liberty, as you know, means somewhere around freedom, so if you are going to lose all your money to gambling, you should have the right to do so, its your money, you can do whatever you want with it. Making it illegal, or doing something that would prevent people from gambling, is not really sounding like freedom, is it? You may limit it if you want, that's a way, but making it completely illegal?
I prefer USA's approach on this, you can't gamble all over the nation, but there are few places you are allowed to go to in order to gamble, most known are Las Vegas and Atlantic City, they seem like the best ones but there are few more. So its really not that much of a shocker.