Do you propose to make all addictive endeavours illegal? Ban porn? It might actually be a good idea in theory, but I doubt it'd work in practice, who knows.
Sports gambling was illegal in most states just a few years ago. Prediction markets also didn't exist. We have ample evidence to show us that it did work fine to ban these things. We aren't talking about some hypothetical world. We are talking about a world that existed just ten years ago.
This isn't a "who knows" situation.
I'm not doing whataboutisms today, sorry.
Gambling is particular, specific burden and crime against society that's been recognized as such for thousands of years.
The recent experiments with legalizing it on an industrial scale are simply experiments with legalizing crime. We don't have to touch the stove but I guess simply being told about what happens isn't enough for us.