ok my opinion...
more than a century ago, England imported opium to China, and many many chinese people(include nobilities AND ordinary people) became addicted. According to the theories above, since opium addicts don't harm the society in form of crimes(because opium is depressant), there was no need to get rid of it. indeed, what opium does as a whole, is that the whole society's spirit was weakended. Different drugs have different effects on human body, but what they do in common is weakening a person's spirit.
In United States, a society promotes individualism, the view of society as a composition of EVERYONE's effort and contributions is often neglected. In other words, we emphasized too much on personal freedom but neglected the responsibility of each individual to make the society a better one.
We can compare US culture with Chinese culture. in US, we will destroy a billion-dollar airplane just to save the life of one person; but in China, the action of sacrificing one's life to save the property of a group is often praised. That doesn't mean that Chinese people's life doesn't worth much, but we should see how individualism has a negative effect on the society as a whole.
Ok come back to the drug issue, let's imagine if we give people all the freedom to use drugs, what will the society be like? It will be totally a chaos. I don't think the moral quality of many Americans is high enough to keep from drugs. When a war breaks out, how can we command a bunch of stoners to overcome another army whose soldiers are not afraid of death and willing to die for their believes? We ask too much what the country can give us, but we never think about what we can give to the country.