They don't want to legalize them because that means abandoning their friends as the tobacco lobby, and the tobacco companies don't want drugs like marijuana to be legalized because that means tough competition. It hasn't really got much to do with safety, because tobacco and alcohol are worse than marijuana.

Look, I'm straight as an arrow when it comes to substance and alcohol abuse, probably to the point of being almost a prick about it (complete and total avoidance of such substances); I personally think it's a real stupid thing you would do to your body. But the way I see it, if an adult wants to abuse their own body then that's their prerogative. Legalize away.