Pen, you oversee the legal side here. Since 1st January, smoking is banned in many public places, official buildings, railway stations, hospitals, bars and restaurant. And in past years, according laws were implemented that cover the workplace as well. The non-smokers in that company simply had laws on their side that said that they must be given the opportuity to work in a smoke-free working place, floor, room, whatever.
You also ignore the originator prnciple (again!
) here. It's not that non.smokers actively cause an additonal effect at set it ffree to the environemnt that harms smokers. It is that smokers harm non smokers by setting additonal agents free into the living envrionment. If your neighbour behaves too loud, the recipe is not that you start to behave loud yourself to "oversond" him, but that he has to turn more silent. Eventually you can even sue him at court to fall in line with that reasonable demand. It is not different with smoking.