People are even vaping on public transit nowadays. Never seen that for smoking.

People used to smoke everywhere. Bars, restaurants, tiny offices without ventilation, cars, busses, aircraft, underground railway, literally everywhere.

When it became common knowledge that second hand smoke is bad restrictions came into place.

You must be young.

Smoking on public transit (and literally everywhere else too) was totally normal and common up until the 90s when regulations started to trickle in. When I was in elementary school teachers smoked in the teacher's lounge and would talk about when they used to be able to smoke in the classroom. My grandma would take about smoking while at work, and she worked as a seamstress.

They appear to think that cigarettes smell bad, yet their nicotine infusused fruit salad/cotton candy monstrosity is fine.