I used to think gambling should be allowed from a sort of social libertarian-ish perspective. Nowadays, I would be in favor of an outright ban in all forms of gambling, betting, or any other name someone wants to give to the same activity, which includes the stock market.

It's a rigged game, and the ones who win are the ones who rig the game to begin with.

No idea how that could realistically be enforced with things like exchanging currencies, crypto trading (which can be legitimately useful if wanting to avoid dragnet financial surveillance using something like Monero or wanting to bypass payment processor oligopolies, like when Visa/MasterCard strongarmed PornHub to delete all non-verified videos as an example of an abuse of their power), scalping/trading physical goods, etc., but at the very least, all other forms of direct gambling with money can be banned in the meantime.