I'm reminded suddenly of the classic "soup Nazi" episode on Seinfeld. I wonder why?
Oh, yeah -- it's the attitude that "It's my gig and I do what I want".
If it isn't unconstitutional to fire somebody for smoking in theiw home, it should be. The whole reason we need laws is to adjucate instances where one person's conduct conflicts with another, and not only conflicts, but damages that other person -- the old "My right to swing my fist ends at your nose" maxim. Here, though, the smoker isn't damaging anybody, because they are smoking at home rather than the workplace.
I can't stand inhaling cigarette smoke, myself, and support the elimination of smoking from shared indoor space because it *does* harm other people. I don't have that right to hit folks in the face, and I don't want smokers forcing me to inhale their fumes. Since nobody is forcing anybody to inhale something against their will here, though, I just don't see the point other than to punish them for something they are only doing to themselves. This sort of authoritarian attitude goes way too far IMO.