I know many smokers that have different logic. They know how bad it is, yet for them it is not hard to quit, but they choose to smoke (often only occasionally or "celebratory" as some insurances call it). Many just don't want to quit, don't try, and accept the trade offs of enjoying their vice vs its harms.

This choice, like many choices involving vices or other intentional deviations from happiness vs wellbeing, are too often assumed to be made in ignorance. This same misunderstanding also happens when one political persuasion attempts to rationalize the choices of another.