I didn't smoke, then I started dating someone who smoked, and who had friends that smoked, and when you could smoke in the bars, it was easy to just take a cigarette and start smoking. So I socially smoked for 3 years, but then quit after moving to CA and getting serious about hiking/backpacking when it hit me that I was hurting my ability to hike. As if the cancer thing wasn't incentive enough.
I hate telling other people what they should/shouldn't do. Well no, I don't hate it, I just realize it is wrong to do so.
The one thing about I smoking anywhere I keep coming back to is this; It takes up more than your alloted personal space and invades other people space. It's like listening to music too loud, or having a really loud conversation on your cell phone in a public place. Nobody else wants to hear it, and we all hate when somebody else does it.
I really don't want to say that people shouldn't smoke in the backcountry. So I won't. After all, fire smells too, but that's a camping acceptable/expected odor. And if I wasn't worried about odors and bears, I'd probably bring a tobacco pipe on a trip or two. But imagine if the campers next to you lugged a boom box out there, and were listening loudly to whatever style of music you hate? Or 1,000 times worse, what if they had a drum circle? You'd want them to turn it down. Cigarette/cigar smoke invades other people's space in the same way. I suppose the solution is to be far enough away that it's not an issue. Or for everybody to realize we don't get to makes all the rules and just deal.