It smells terribly, exposes others to negative health effects without consent and is one of the biggest causes of littering. Simply put it is a major nuisance with no benefits apart from profits for the tobacco/drug industry and addicts getting their high.
Could probably extend that to anywhere around minors in general too.
I think they mean outdoor places, too. I don’t recall that being common. I assume they’d also be against designated smoking areas, since that doesn’t fix all secondhand smoke to leave them around.