There are other ways to handle abuse and addiction besides trying to prohibit a widely-desired substance. You rightfully point out that some people have huge problems with alcohol. The solution isn't just to blanket make it illegal (with the ensuing chaos that would/did cause), but rather directly address the acute harm caused by the people with the problems.

Ultimately the reason we consider some things natural rights isn't to create some prescriptive model for the shape of an enlightened society. Rather it's due to the inevitable ugliness when the government attempts to legislate into individual autonomy, and people react en masse. And the results of the "drug war" have most certainly been quite ugly!