Of course drugs should be legalized, especially marijuana. If you ask most people for the reasons why drugs should be banned, all they'll end up saying is "drugs are bad" and wont back it up with any sort of legitimate arguements.
It's like those anti-marijuana laws you see. First they said marijuana caused cancer and damaged the lungs, but then there was a study showing that there was no link between marijuana and cancer, as marijuana is not cultivated in radioactive soil like tobacco and also contains no natural chemicals that are harmful to the human body. Second they claimed it caused memory loss, but when you looked at the specs of their research, you'd have to basically smoke close to 70 grams a day for it to even hinder short term memory. And the DEA was responsible for the research.
They tried to say marijuana is a gateway drug, but in a study commisioned in 1939 by then NYC mayor Fiorello LaGuardia proved that this was not so. Now they just go with stupid messages saying that if you smoke pot you'll end up losing your friends and sit home all day.
The DEA seems to just ignore published studies by universities, doctors and critics. It just picks old information mostly based on moral ideals rather then facts. It uses this bs to justify banning medical marijuana on a federal level.