Actually that’s the STRUCTURED progression when one country decides it wants to get another country hooked on a drug. Opium was legal in most of the world and didn’t have the problems China had. Remember the Opium Wars was actually China trying to STOP the drug coming in.
I disagree with your premise, but for the sake of argument let's just say it's true? By what sort of Naive thinking do you believe that wouldn't happen again? How are you gonna stop it if drugs are legal? You don't think the Columbians and the Afganis wouldn't ramp up production in an effort to "get another country hooked on a drug"?
Remember the Opium Wars was actually China trying to STOP the drug coming in.
In this case, the Drug dealers (the British) had more firepower than did the government of China. In an early effort to halt the flow of opium, one Chinese official burned a large shipment of the drug. (In Shanghai I believe.)
The British responded by bringing in warships and mercilessly shelled the town killing thousands. The Chinese begged for peace, and so the terms were dictated to them by the British, and those terms were the legalization of the Opium trade. People who want to talk about legalizing drugs should seriously study this period of history.