Earlier quoted context omitted.
Why isn't cocaine legalized? Honest question - I've never done it nor have a I done a ton of research.
Because there's always the risk that someone will try it out of curiosity. And since it's a highly addictive drug you might end up causing more problems than you intend to solve.
Same addict in two societies.
Society 1) Drugs are regulated in pretty much the same ways they are in the US, and because of this prices are high. The addict may have a family or maybe not, but has bills to pay. He spends all his money on drugs leading to neglect of his bills. He gets arrested and is now unable to hold down a job. This leads into other problems after he gets out of legal trouble. He now has to steal to obtain the drugs.
Society 2) Drugs are largely decriminalized and cheap enough that a days supply for any addict don't break the bank. He doesn't lose his job because of legal ramifications and he just spends all his free time doing cocaine. He doesn't have to steal to obtain the drugs.