I'll probably get flamed for this - but I can't say I totally disagree.
Heavy and even moderate smokers are more likely to develop health problems from smoking. You can't disagree that health costs would be different if people would stop lighting up. Yes, that's not the only reason for health costs.
Yes, I realize the slippery slope argument that was identified in the article...refusing to hire people who aren't the ideal weight, etc.
But from where I sit, purchasing health care (either in full or in part) is a contract where you agree to maintain good general health habits and they agree to cover you when you're sick/injured. Sucking on a pack of cigarettes a day seems counter to that.
Kevin