I agree that there's not much of a difference, but the legislature would be there not to arbitrarily penalize self-destruction more than to facilitate justice for people who aren't hurting anyone (as opposed to facilitating justice for those who are hurting people around them).
Slippery slope on the "where do we stop, then?"--textbook definition of slippery slope, even. Regulating salt? no.
And I don't really see what's so "tedious" about wanting to experience clean air when in public places. I'm not going to pull your cigarette out of your mouth and give you a lecture on why I'm better than you (although I might think about it)--I really don't care about you that much.
What annoys me is that it really is a tough issue, when the few subjective claims smokers can really make always sidestep directly replying to my rights as a chronic asthmatic to breathe comfortably in public places.
Interesting to note legal issues concerning failed suicide attempts . . . not that I remember what they are, or would bother looking them up right now, but, noting scientific documentation over the last 50 or so years, it is a hell of a lot more like passive long-term suicide to smoke than it is to eat lots of salt.