Well, the Church doesn’t say smoking is a sin, so it is not. I think there are just a lot of people who wonder why it isn’t. I don’t believe addiction is a sin per se. I just wonder where the line is drawn. Most intelligent people know the dangers of cigarette smoke whether they admit to it or not, or whether they want to agree with it or not. The evidence is there. If you know something could be potentially life threatening, potentially addicting-- when does it become sinful when you partake of that?
Smokers will always argue that everything we do has the potential of danger… driving a car, living in the city, eating anything that’s not nutritious… etc. However, there’s nothing about a cigarette that is healthy no matter what the tobacco industry would like to sell you on that. Directly inhaling pollutants into your lungs really serves no purpose other than personal enjoyment. People get a buzz from smoking, or they calm down, or it’s just a habit. But again-- you are using a body part intended for sustaining your LIFE for your enjoyment. Not only that, but the activity is actually harmful! That doesn’t seem any different than a few other sins that are deemed mortal. In fact, it seems worse. Again, I wonder why the disparity? My guess is because there was probably a Pope or two that smoked.