You are aware poppy is used to make morphine and codeine? Point in fact, morphine is practically the same thing as heroin. Morphine is a great drug for people recovering from surgery and others in severe pain while hospitalized. Codeine is excellent for somewhat more minor pain relief. I can't believe anyone would be against these drugs, considering the amount of pain they prevent.
There are also, of course, poppyseed oils (for a variety of uses) and poppyseed used in various foods.
In Afghanistan right now, it is illegal to grow poppy for ANY REASON. It doesn't have to be legalized to make heroin or opium (I consider that a separate issue), but I can't think of any reason it shouldn't be allowed for more legitimate purposes.
Heck, I'd love to see TOBACCO banned . . . . I hate the vile stuff, and it is downright deadly to the user.
Cigarettes certainly are with the way most smoke 'em. The high balling of tobacco deaths irritates the crap out of me though (smoke 5 packs of cigs in your lifetime, die of cancer or heart disease, and you're considered a tobacco death).
A good cigar, however, is a wonderful thing.