Maybe I'm an outlier, but I couldn't care less if people smoke. I believe in letting people do whatever they want to do, as long as it doesn't hurt me. I'll accept the small risk of breathing second-hand smoke.
For decades, people were allowed to smoke on planes. It can't be significantly dangerous, or it would have been banned long ago. And the current ban is primarily health-based, I believe, not safety-based. Someone else may know more about that.
Bruce