We could extend this to a lot of stuff - bars serving alcohol is reliably and consistently giving negative outcomes, right? People get drunk and beat their wives or kids pretty often, they get in crashes, they drink away their liver. Do we ban that?
I'm sure you're aware of Prohibition, but yes, we did ban that. Didn't work very well, though, and we unbanned it (with a minimum age limit).
When smoking's health problems became well-known we only banned advertising (and maybe selling to minors?), so maybe we still remembered the lesson from Prohibition.
