You're all missing the point. Some statistician worked out that nicotine use likely correlates to age and this gives them a way to fire old people.
https://www.hirevue.com/blog/what-is-adverse-impact-and-why-...
However, I'm not sure it actually applies here given the surge of nicotine vaping in young people.
This is still basically being used to discriminate against older applicants.
It's a nicotine ban, not a smoking ban. That means vapes too, which means plenty of younger workers tossed into the mix as well.