I don't think that it should. There seem to be more excuses than actual reasons to legalize it:
- "the war on drugs has failed" (<- so yeah, let's legalize it then(?))
- alcohol is legal (yes, when you're 21), and causes just as much/more damage than marijuana (<- so?)
- marijuana doesn't (permanently) "harm" you, but it does influence you (your mind, mood, judgement and REM cycle)
- "Marijuana deserves to be studied for its medical property as well as to how it can psychologically affect the user." <- it actually has been studied; just look it up (make sure the articles address pro- and counterarguments).
- "Who am I, or you, to say what I or you can put in your body?" <- like someone else posted, it is a matter of not only private but also public safety.
- Unlike alcohol, the effects of marijuana are more longterm. If alcoholism is a disease, then being a pothead is just as damaging (also to your wallet)
- as being used for medical purposes, I don't see the use of marijuana doing a better job than a health spa (more beneficial to the economy/employment as well); in Europe, they were a common solution for people with anxiety-issues before WW2 (even before WW1). I believe in Japan it's still a common place to go to for anyone.
- marijuana will probably be used for pain treatments and PTST, but while marijuana may inhibit (short-term) stress, there is a good chance individuals experience anxiety ("bad trip") anyway (and an altered REM cycle, as I mentioned earlier). Also I don't really see how marijuana is better at relieving pain than morfine injections. I don't know anyone who relieved their physical pain/clinically diagnosed stress with marijuana (succesfully); and I live in a country where its usage is legalized. It's not like no one here came up with the idea yet.
- it takes a lot of energy (in the form of greenhouses, lights and water) to grow marijuana plants; it costs (economically/environmentally) more than it yields, except when you charge more for it than the government can probably finance.
I think a lot of people (who aren't users) are curious and want to see the drug being legalized to see what happens next.