It’s true with gambling too. You just likely haven’t seen the harm that happens because of it being illegal. Ever had a gun pointed at you over a game of poker? I have. Doesn’t happen online or in a casino. Ever met people who’ve been violently hurt because they couldn’t pay their gambling debts? I have. Draftkings or your bank aren’t out breaking knees.
Making it illegal does not make it go away. If you had been born into a world where alcohol was illegal for a long time, and then it were legal, you’d probably have the same opinion of that, but you know (because you were lucky to be born with the benefit of decades of hindsight) the world is less good that way. This is not different.
The harms of gambling can be mitigated much more effectively in ways other than prohibition. Regulation is always better than outright bans. Look at what we’ve done with cigarettes.
Making online betting legal was the right thing to do, it being illegal at all was the mistake, we just need to work on harm mitigation.
I just don’t even understand people who think vices should be illegal. I mean I do, their thought process is just overly simplistic and they don’t know what they don’t know, but there’s just so much evidence it is the worst possible solution and yet so many people can’t think past “it’s bad so it should be illegal”. Even intelligent people.