Smoking isn't bad.
I get rather sick of being demonised; I'm a smoker, and I'm also a decent person.
More likely, trashy girls like that have learned from their parents nothing good. For example, their mothers might have taught them by example that the only thing they need to get on in life is a great body. A lot of these girls are also taught not to respect themselves or their bodies, and that getting a man is the one goal.