kallahar writes Why does the government prohibit certain drugs?

Is it to protect users from harm? No, that can't be the reason, because users suffer more (adulterated drugs and jail time) when a drug is banned as compared to when it is legally available, and besides, the most dangerous drugs of all - alcohol and tobacco - are legal.

Is it to reduce the crime associated with illegal drugs? No, that can't be the reason, because banning a drug always gives rise to more crime (drug cartels, petty thefts by users as prohibition makes drug prices much higher, violent disputes between dealers) than when the drug is legally available.

Is it to distract our attention from more important issues (and to provide bigger budgets and free drugs for our police officers) by conducting a brutal, Hitler-like pogram against the innocent few who ingest or sell certain drugs?

Bingo! - DrugSense.org