Nobody I know respects a person less because they smoke so this generalization is therefore incorrect. If this is your personal opinion then you are, of course, entitled to it.
Since you dislike smoking I'm not sure why you have a problem with a smoker stepping outside to smoke, but okay.
The generalization is correct, people’s respect for a person, especially a male, drops when they see him anchored by a old timey cigarette addiction.
It is especially noticeable if one lives in an upscale region like the Southern California coast where smoking is pretty rare, and then visits an area of low education.
Today, smoking is a habit that the poor and uneducated practice because they can’t help themselves, smoking is rare among the educated.