That long-term cigarette smoking can lead to health problems including cancer and lung disease is a scientifically well-established fact  Contrary to what many people seem to believe, however, it is not necessary to deny this fact in order to reject the view that tobacco companies should be held either morally or legally responsible for the poor health of smokers
After all, excessive consumption of candy undeniably leads to such health problems as tooth decay, but no one seriously believes that candy eaters who get cavities should be able to sue candy manufacturers
if candy manufacturers were held responsible for tooth decay among candy eaters then tobacco companies should also be held responsible for health problems suffered by smokers