As a retired high school teacher, I cannot tell you how many times I smelled marijuana smoke in stairways or halls, or witnessed obviously high students in my classes. They were dreamy eyed, not 100% connected, and their normal social inhibitions were missing, so they'd blurt out just about anything. Thinking about this first-hand experience at normal thinking processes so changed by weed terrifies me as to the effect on driving or operating dangerous machinery. How would you like your airline pilot high on weed? Or the air traffic controller? Or those monitoring nuclear energy plants? Or the guys driving to the left lane and right lane of you?
And this was while marijuana was illegal for all ages - giving sellers no incentive to not sell to kids. Kids have reported for years that they can get pot almost as easily as beer or cigarettes, although the latter are far more prevalent among adults.
How would you like your airline pilot high on weed? Or the air traffic controller? Or those monitoring nuclear energy plants? Or the guys driving to the left lane and right lane of you?
I wouldn't like them drunk - but banning alcohol would do little to solve that problem while punishing innocent users.