FWIW, it's actually been working quite well in most states since the 1930s and all states since the 1960s . Repeal of Prohibition - Wikipedia, the free encyclopedia<--This is fairly solid evidence that these slippery slope arguments are unsound. They have no logical or empirical basis. We don't create addicts by making safer products AND informing them, and the rest of the public, of the risks. The 'reefer madness' mentality is more likely to do that by enticing the young to get involved with things that are deemed "bad".
The real issue, again, is safety. A monitored, controlled drug market is safer than the black market we currently have. The mere existence of such a thing will not create addicts. It will just keep them, marginally, safer. Even more importantly, it will keep those of us in the cross-fire much safer.