> What you say would be true if any form of addiction were a choice. But it's not. Even addictive behavior is governed by brain chemistry so it is, in fact, chemically induced.
ALL behavior is governed by brain chemistry, NOTHING is a choice, in the philosophical sense, the brain is an bio-electrochemical computing device.
Yet none of that matters in the free market analysis of modern day microeconomics. Utility is utility, whether that is earning money, playing video games, or taking any drug.
'Addiction' does not alter the fundamental theorems of welfare economics in any way. A free market leads to an optimum where everyone is better off, and no one is worse off, and no one can be made better off without anyone being made worse off. Furthermore, any violation of the free market assumptions (such as criminalising drugs, which is a negative externality on drug users) means that people COULD be made better off without making anyone else worse off.
At best, 'addiction' should be a medical or health issue, not a criminal, and not an economic issue. Addiction, from an economics point of view, is simply the difference between a person's stated preferences, and their revealed preferences.
You should concern yourself only with your own drug taking, and not force your beliefs on others. Let people make choices that provide them with maximal utility, as long as they aren't impacting on you, it's none of your business.