Just as miners know the risk and hazards of mining, servers at places that allow smoking should know the risks associated with it. No matter the job you assume the risks that go along with it. Doctors and their secretaries could be exposed to the flu, should they ban people that have the flu from going to the doctor? If the person does not like that work environment they should not apply for a job there. I don't like working on roofs in 90+ temperatures during the summer, so I'm not a roofer.
The thing that is stupid about the smoking law(at least around here) is that all the smokers huddle just outside the door, so you get a great taste of smoke as you go into and come out of the bar or restaurant. Its not much of a problem during the summer, but during the winter its worse as people aren't hanging out outside when its snowing out.