Just like non smokers can have friends come over their house to drink.
You see, if the few bars out there that do in fact serve food, then I agree that they shouldn't allow smoking inside. Most bars I've been in though(in CA at least)don't serve food, only a really small percentage did. I'm talking about real bars of course, not the bar "area" in an Applebees or some other restaurant. Now maybe that's just in CA but if there is no food served I don't see a problem with the owner allowing smoking.
Just for arguments sake your saying that an owner of a restaurant should be able to have the right to cut vegetables with the same knife he used to cut raw meat? That's a food violation. Now while inhaling smoke, whether first hand or second hand is also bad for your health and dangerous, food violations are a whole other ballgame and have been set in motion way before all the smoking bans came in place.
All I'm saying is that having non smoking bars is entirely fine but I think some of the owners out their should be able to choose to allow smoking if they want. If you don't smoke, then just don't go to those bars since I'm sure there would be plenty of bars to choose from that have the ban.