holy cow, chad. Forgive me for not reading what you wrote---(unless you are willing to give me CEUs for it so I can use it to maintain my sub abuse license, that is...
I agree that it should be legalized, regulated, and taxed just like alcohol and tobacco. As far as harm, it is my understanding that the amount of carcinogens (sp?) and other harmful chemicals are the same, if not less due to the "organic" nature of pot. What I mean, is that most pot smokers and growers do not use any chemicals in the preparation of their weed for smoking (unless, of course, they are lacing it with something to enhance the effect.).
The inhalation of pot smoke becomes detrminental more so because it isn't filtered, meaning folks usually smoke it wrapped in a paper or "blunt" (hallowed out cigar) that usually doesn't have a filter on it to help take out some of the chemicals, etc.
From what I have read and been taught, the addictive nature of pot is similar to cigarettes and it is often called the "gateway drug" because as people's bodies get used to it they will often move onto another drug to feel the same high they used to get. That is why they sometimes lace it with things to aid in the effect. I kinda liken it to beer drinkers who end up going to hard liquor because "beer doesn't get me buzzed." sorta thing.
Like I've said before, if it is legalized then there can be some sort of regulation of it. Pot growing is a lot like making your own beer or wine. Once you get acquainted with the art of doing it, you can learn how to increase or decrease the addictive (mind-altering) aspects of it to your liking. I think our government should legalize it and tax the crap out of it.