I think part of it is that anti-smokers will look in non-smoking bars and see that they're dull and lifeless, and they'll look in smoking bars and see people having a good time, and decide that it's not fair that there isn't any smoke-free place they can have a good time like people are having in the smoking bars.
Somehow it never clicks that there might be a reason the non-smoking bars are no fun.
I think the law is intrusive. The laws prohibiting a guy from tossing a football around in Central Park with his six year old offend me more and Rudy was in Gracie Mansion when that happened. NYC is changing, becoming more "polite". Both situations are symptomatic of this smoothing out the edges. I'm a non-smoker who enjoys an occasional stogie. I like the cleaner air and the lack of someone else's stink on my clothes the next day. I think smokers are idiots, given the inescapable long term issues. That said, I would not have approved the law if in a position to vote on it.