Do I think that current drug laws are perfect? No. Marijuana is probably over-regulated, and society would not likely fall apart if it were legalized in the US. A law that prevents someone from using an incredibly destructive substance is not an arbitrary law: it is a law that is meant to protect people.
And yes, some people need to be protected from themselves, because they lack the capacity to make responsible decisions. Case in point: it's no secret that it is easy to become addicted to heroin, and heroin will ruin your life . . . yet people still do it.
If you are caught selling drugs, you will go to jail, and it will ruin your life . . . yet people still do it.
Tell the child of a drug addict that everything is okay, because drug abuse is a "victimless crime." Tell the parents of a crack head that it's all going to be alright, because "it's his choice to destroy himself." The next time you complain about taxes being so high, remind yourself that you shouldn't be mad because the money someone gets for disability--because drug addiction is considered a disability--is well spent, because you're just funding their ability to be free.
Go find a junkie and pat him on the back and tell him "congratulations, you're exercising your right to kill yourself!"
People should be free to run their lives as they see fit, but not at the expense of everyone else. Anti-drug law proponents seem to think that the only related cost of drug abuse comes from the enforcement of drug laws. The truth is that most people who argue in favor of complete drug legalization simply do not know the cost of cleaning up a junkie's mess.
If you believe that all drugs should be legalized, then I have a few questions for you. How many junkies have you met? How much time have you spent in low-income areas in which drug addiction is rampant?
If you truly believe that drug addiction is a victimless crime, then my guess is that you may not have much experience in working with that particular population. Just an observation from someone who has experience working with them.