Have you ever been around cigarette smoker when you have a cold? I don't think you quite understand how much smoking/vaping is saying fuck you to those around you.
What I'm getting is that you don't like something and think it should be fine to discriminate against those individuals. If this is the paradigm we're going for, then let us also discriminate on politics, clothing choices, speech accents, etc. Why should we employ people who we don't agree with?