Why do directors feel that they have to carry realism to such extremes in having the characters smoke on stage?

My characters smoke in many of them, and they look cool and glamorous doing it.

Sharon Stone's character smokes; Michael Douglas's is trying to quit.

Many characters smoked in the shows, including the stars.

In the film, Tim Holt's character smokes a cigarette and has a drink, which was unsual for cowboy stars at the time.

The character, she goes on, usually wears red hot pants, a macrame top and spiked heels, and smokes incessantly.

Its under-age characters smoke marijuana and use profanity.

In any proposed movie or television scripts, the characters cannot smoke or drink.

My character will smoke a cigar, even if you don't like it.

I wanted to know why people smoked, why my character smoked.