I don't see how it is junk science. I hate it when people have no respect for others and smoke right outside a public entrance. Yes, you can step around it, but you shouldn't have to. If people are off a ways, that's fine, but I don't like the smell on me and my clothes. That's a simple courtesy, not junk science.
I can see your private property point (say that three times fast). People should have a right to smoke around their private property.
More often than not the only reason the people are standing outside is because of stupid smoking bans. If they were allowed a room inside or be able to smoke inside the bar, they wouldn't be outside at the door.
Plus add #3, Republicans who are for smoking bans are generally hard core RINOs on everything else.
Pataki, Rowland, Bloomberg and Bruno for example are more to the left than most Democrats. You see a Republican supporting a smoking ban it's pretty much guarantees they are a RINO in regards to everything else.
personally, i hate smoking bans. i am friends with many restaurant owners (none of whom smoke) who oppose the bans knowing that if people can't smoke, they will go elsewhere. bans can be very bad for business.