What is the point of preserving human life if all of life is pain?
Because it'd be a lot more painful with a black lung. 
That's exactly the level of immature teenage mindset that makes such a compelling argument in favor of this measure.
I'm sure most cocaine addicts believe that cocaine should be legalized (obviously not the same thing, but still). Even if you are a smoker, the idea that anyone's happiness is exclusively dependent upon smoking is ridiculous. I don't pretend quitting is easy (my grandfather said it was absolutely brutal for about one and a half months after he quit and he relapsed every now and then for about a year), but I don't see how you can credibly claim that smoking is a good thing. At the end of the day, it is highly addictive, very dangerous, and can lead to other people getting addicted too. Part of why I have no issue with marijuana is that it simply isn't a danger to the user or anyone else. With alcohol (arguably one of the more dangerous legal drugs), I can easily see the argument for raising the drinking age to 23, but I think that wouldn't do much since society sees underage drinking as a harmless vice at most and you have to be realistic about this sort of thing. Smoking is generally seen in American society as a fundamentally bad thing, so I don't think you'd see the same level of effective long-term resistance that you would to raising the drinking age.
