Living in a society is by definition not about granting total independence and freedom.
You do not trade in your freedom for a drug free stable society. You trade in your freedom for nothing, then get the exact same shit but with a fresh lie to your face that it ain't like this.
Because it's another one of those things that "your betters" think they control about your life, and with the attempted rollback of things like abortion rights in many places is very relevant. Also we're seeing news out of asian countries of fertility rates falling below 1 you should really expect the more authoritarian governments to say "Have a kid or have a problem" pretty soon.
Addiction isn't some disease that can strike randomly, the science shows that people who are already unhappy/unsatisfied/deprived are much more likely to succumb to addiction. Addressing the societal problems behind that would go a long way towards eliminating problematic addiction, and conversely banning all narcotic substances wouldn't stop those people from finding other ways to harm themselves, like alcohol, gambling or overeating to fill the emptiness inside.
Having mildly addictive weaker drugs available and cheap helps prevent the development of stronger and more easily smuggalable drugs.
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[0] https://en.wikipedia.org/wiki/Opioid_epidemic_in_the_United_...