You have to remember us smokers are bullheaded - facts do not matter much.
I'm in complete agreement about our maverick natures, but not to the extent that all of us ignore inconvenient facts.
Some of us work with them, factor them into the equation; what continuing to smoke will ultimately cost us can't be known with precision, but statistical probabilities can, and a rational quality-of-life vs. life-itself transaction can be made.
A non-smoker has zero understanding of the value we find in smoking, a habit they likely see as simply a destructive, expensive form of nail-biting--and a deliberate decision to do it an act of calculated, controlled suicide. Yet it's the same cradle-to-grave mathematics they've chosen for themselves every time they've shaved seconds off the back end of their own lives by eating a Twinkie.
I suppose the good doctor has to be cut some slack, in that his oath to "...do no harm" isn't intended so broadly as to recognize that a monastic, uncompromising lifestyle is a life worth living for only a very few.