I think you've got it right there. You can ban selling or possessing something like alcohol, but you can't remove it from the world, because you can't remove the process of fermentation. Nor can you remove the tendency many people have to abuse otherwise harmless substances or behaviors. I'm frequently amazed at the substances people will mix and/or imbibe to alter how they feel. Even those who choose not to use chemicals can do other dangerous things. Helping people find ways to cope, and to avoid situations the lead to dangerous choices is a lot more practical than hoping that banning one substance will fix a huge problem.