Drugs are bad...m'kay?

In looking at the mass incarceration of drug offenders and the related loss of public money, loss of fathers and mothers in families, loss of community members, and loss of so many other things, I think it all goes back to and stems from morals. People are in jail because they used, possessed, manufactured, or sold drugs. As a society, why do we care about that?
Everyone has decided that drugs are bad. Why are they bad? They are bad because people use them. What happens that is bad when drugs are used? I think the general consensus is that: People are lazy, go crazy, or turn to the dark side.
I think that these are some of the commonly held beliefs out there:
Pot is bad because people are lazy or become forgetful or stupid.
Hard drugs like cocaine and heroin are bad because people lose their minds and commit crimes like prostitution, robbery, and murder in order to get more drugs.
Exstacy is bad because it will make you party too much and have sex with people.
Meth is bad because it makes you unhealthy and crazy.
All illegal drug users are neglectful to their families and communities.

My question is, why do we care what someone does to their own body or to their own life?
Ideas:
1. We care because drug abusers cost us money.
2. We care because drug users are a threat to our safety.
3. We won't allow people to do damage to themself.
4. We care because it is hedonistic.

Idea #1 can't be right, because we gladly spend half of the federal prison budget and a third of the state budget on incarcerating drug offenders. Each prisoner costs us between 20 to 40 thousand dollars a year, depending on the facility.

Idea #2 has some merit. Just like drunk people, people that are high often make poor decisions. However, most of the threat is created by the illegal nature of drugs. Any time there is a black market for something, there is the associated violence that comes with it. I do believe that some people are so unfamiliar with drugs that they are terrified of people that use them and would prefer to have these people behind bars.

Idea #3 is strange to me. Why can't adults decide for themselves what they want to do or what kind of life they want to live? This idea seems wrong. Smoking is legal, alcohol is legal, Burger King is legal... obviously we don't regulate the other ways that people can kill themself.

Idea #4 Could the idea that pleasure seeking is wrong play into our policies on drugs? Our Christian roots might influence our laws. Sex for pleasure is wrong. Lust is wrong. Greed, sloth, gluttony... these are sins. Drug use for the purpose of selfish pleasure seems to fit nicely in that SIN category.

Conclusion:I think that ideas of right and wrong and morals get intertwined with drug policy. This doesn't seem right in a country that promotes free thinking and freedom of religion.