When director Taylor Hackford's Ray Charles biopic was released, he was attacked by the astro-turf anti-smoking flash mob.
Seeing an ad with an athlete (or anyone else remotely admirable) might make a smoker realize that perhaps there is nothing inferior about them after all.
Banning cigarette ads is not only a form of censorship, but also a form of propaganda. When nobody sees people smoking in any media, they are slowly trained into thinking of it as an abnormal behavior. Abnormal behavior means "abnormal" people are the only ones who would do such a thing.