Earlier quoted context omitted.
> the libertarian in me thinks that people should be free to do what they want to their bodies provided it is not at the expense of society as a whole society is burdened in the 50% chance scenario that they develop lung cancer, alongside other medical problems which smoking exacerbates as well as being a contributory factor to others.
People die of something. It costs no matter what that is. So there's some extra cost since they're dying sooner (maybe?) It's more complicated than 'Hospital costs!' since those are pretty unavoidable no matter how you die?
To be more succinct, there's a large difference between a person requiring lengthy treatment for lung cancer(hospital + morgue) before ultimately dying compared to somebody dying due to old age(morgue).