For a while, we had tons of alcohol and cigarette ads. At some point they were both deemed catastrophically harmful to society. Maybe prediction markets end up there?
unfortunately the dominant ideology right now states that the ability to do catastrophic harm to both yourself and society in general is fundamental to the nature of freedom, and is therefore paramount.
That's the argument we heard back then too. Smoker's rights to spray cancer to everyone around them. Drinker's rights to smash innocents on the roadways. In reality, the tobacco and alcohol industries lobbied hard to protect themselves. Alcohol is still lobbying hard to prevent recreational weed.