As others have pointed out: addiction is way to vague. Are we talking physiological or psychological addiction? And addicted to what degree?
Several medical studies have also pointed out that it's no more physiologically addictive then a pack of cookies. Now, I'll grant you that psychological addiction may occur with marijuana, but the same thing can be said of any one thing in the world.
Your hand waving about how it's addictive has just about as many facts in it as people who claim it's not addictive (without the sources to back it up). So, what are your sources for your claims that "Find me a meth or Heroin user that did not smoke pot first" and "It's about getting "high", and that eventually ends up into finding alternative highs."?
I'm genuinely curious about this "gateway theory". Also, where I'm from smoking pot is legalized here, oddly enough, we don't really have a problem withe heroine usage skyrocketting., in fact, if this site is to be believed we actually had a decline! (http://drugwarfacts.org/cms/?q=node/67)