No one is born addicted to cigarettes, but whether one is predisposed to becoming addicted to smoking depends on a confluence of physiological and environmental factors. This is why the "stickiness" of smoking varies from person to person.
Heavy smokers typically have a someone in their life who, indirectly or directly, introduced them to smoking. This may be a "cool" friend or older sibling. It could also be a respected/loved parent or grandparent who simply smoked in the presence of the child.
Heavy smokers also have a strong pleasure/reward response to nicotine. Like anything else, this response varies from person to person and as a result, some are repulsed, some are ambivalent, and some become chain smokers.
The bottom line is that the decision to start smoking and whether or not one continues is not rational.
Smoking was not particularly "sticky" for me personally (smoked on and off for a few years in high school and college), but when I decided to quit I had no problems.
However, this does not give me the right to assume that everyone's experience is the same as mine.
If someone wants to do right by their health in one area, and is dealing with an addiction in another area, they are at least trying to do right by their health in one area.