What you think about prohibiting the sale of drugs, alcohol and cigarettes?

Nowadays almost all people smoke,take drugs and drink alcohol.Written on cigarette packs that smoking harms for health.No I do not understand why they still sell them, and people are still buy them.Why now all say that smoking is fashionable?If you want to live longer, why do not you stop smoking, drinking or taking drugs? Or why not buy it ceases all?
Think about my words.You have people who value with you.So why you're so hard to reciprocate REPLY?