(thought I posted this earlier, but it seems to not have got there)
My mum is allergic to smoke. Even one single smoker in the room can mean she has sinus pain for days afterwards. So the only chance she has to go to a folk club is if there is one nearby that is non-smoking. Our local FC is nonsmoking, and we are really grateful for that. Otherwise she'd have to stay at home.
A friend is asthmatic, and finds that smokey environments affect her voice so badly that she cannot rely on it - hence she doesn't sing. That is a real loss because she has a really lovely quality voice.
I am not allergic or asthmatic, but still find smoke affects my voice - so my preference is to go to non-smoking venues.
These are solid reasons for being very glad that there are nonsmoking clubs available, not touchy-feely or trying to spoil anyone's smoking fun.