Because much like with Prohibition back in the 1920s. the advantages are far outweighed by the disadvantages.
Yes it's undoubtedly true that the ban of liquor did work. It did kept alcohol abuse down, and it curbed consumption among the general public, BUT..........Those few benefits were not worth it when organized crime came about. There were so many bootleggers, and rum runners that they were making a shit ton of money off of liquor on the streets, they soon became so big that the authorities couldn't bring them down. As a result violence went up among the cops, criminals, and even innocent people over money and booze.
Same thing with cannabis, Mexico is in bad shape right now because of the violence the cartels brought over when they got a hold of the cannabis market.
Say what you want about why you don't want it legalized but you have to understand that the current laws are not going to stop people from using it. It's only going to make them into criminals whether through the black market, or by throwing them in jail.
The whole motive behind demonizing cannabis is very similar with the controversy behind absinthe. Much like with the textile, oil, and paper companies, the wine industry of France didn't like it that people were liking this new drink (absinthe) so they found ways to demonize it. Like with the cannabis they claimed it rotted your brain, and caused other health issues. Absinthe distilleries are now back on their feet after the govt. of France lifted the ban; as well as in the in the US (in 07). Hopefully this will happen to cannabis as well and end all the BS scare tactics.
