I think we are probably making different points here. It sounds like the point you are making is that human life has no particular value and therefore spending time on activities to extend it (or educating the public about ways to extend it) are not worthwhile. My career is based on helping people extend the length and quality of their lives. Based on that, yeah, I think cigarettes are bad. If ones philosophy is that you're born, you die and who gives a crap about the details or those you leave behind then sure, light up.
In regards to how would I have felt about a loved one who died in a car accident? I would be devastated either way. And if that had been preventable (like wearing a seat belt) I would have wanted them to take that step so that they didn't die.
Again, I'm not making the argument that you are a bad person if you choose to smoke. I am saying that you are delusional if you are making the argument that doing so is not bad for your health.