It's not out of kindness, it's laws that many cities and states passed in the 00s to ban smoking in various places (and eventually everywhere indoors altogether in most places).

I think it's a state and local level thing here though, so it's going to vary by location. I'm referring to the US if it wasn't clear.

I think it's less so a matter of politeness or kindness and moreso because one of the few great projects within the US over the last 50 years was the war on smoking. From the banning of smoking adverts to the anti-smoking PSAs of the late 00s and 2010s there's been a consistent push against cigarettes specifically, also it's expensive with high taxes noone has the cash for that.