Also, even the sources that argue for the legalization of marijuana say that it does not actualy treat any known disease, it aleviates the symptoms. Its not yet proven that marijuana prevents cancer or treats glaucoma, in fact it might worsen it a bit due to the carcinogenic effects of smoking, much like cigarettes, in regards to lung cancer.
I realize smoking pot isn't suddenly going to make your life suck in health aspects, I argue against it because it isn't the panacea most claim it to be, isn't going make anything necessarily better, and in general provokes a negative reaction to the larger part of society. Sure, that reaction is part of a problem that needs to be fixed, but society is a harsh thing, and hoping a friend doesn't suffer from that kind of reaction isn't too bad on my part, is it?
Plus, like I've said before, almost every single person I've known that smokes it doesn't seem like the kind of people I wanna be around or lead a life I'd wish for anyone I like. I'm not a purist, I just have a general distaste of things that alter my perception in some way, which is why I don't drink alcohol regulary, and the only reason I don't smoke is because I hate the smell it causes.
Yes, smoking pot isn't the end of the world, but generaly disliking it doesn't make me a crazy extreme right wing facist either.