[WorldMaker]

A direct comparison is to the tobacco industry. Tobacco sales still remain legal in most of the country, but for multiple reasons there's been huge restrictions on how and where and to whom (no marketing to minors/kids) tobacco companies can market. Tobacco products have to be marked with big addiction warnings, and very visible reminders of side effects. Tobacco products also generally have taxes collected specifically to directly finance anti-addiction resources in many states.

Legally selling the drug is orthogonal from morally/ethically dealing with the consequences of the drug, including regulating how it is sold, how it is marketed, how it deals with its own consequences.