So what's the harm of vaping? As far as I know, there is some evidence of harm, but it compares very favorably to smoking. It's a different class.

To talk about "years of life lost" is quite off from what I know about it. And I never vaped, just smoked.

Yes, it seems like the elder generations are benefiting greatly from vaping but the "kids these days" are having huge issues with it. I agree that majority of a high school will just suddenly be all in on vaping, the social pressure is just waayyy too high in a place like that and a bunch of people get pulled in that wouldn't just cause a couple of the more influential ones picked up something they view as a toy, but that they can portray as a status symbol, at least within the high school.

I will say that when those juul kids come to college, very specifically my college, they hit the reality that everyone there still looks down on it and that they're basically just broadcasting their "highschoolness", and then they realize how hard it is to quit. We had smoking at my non-smoking campus, just behind one of the buildings, but it was by definition not popular. Vaping existed but if you were walking around blowing huge clouds of cotton candy shit, people would both actively avoid you and look down on you. It was the culture at the time.

Disclaimer: I left a couple years ago, that was my experience, things could've greatly changed by now

"My understanding is entire high schools are getting addicted to vaping, where before smoking was a relatively minor phenomenon. I suspect vaping is causing multiple times as much harm as it is providing relief, especially since they target young people for new customers."

I think I'd want a citation for that. It's been a long time since I was in high school, but smoking was incredibly common (if reasonably well concealed) back then. I can see vaping as being somewhat more popular (if not "entire high schools"), but...

I suspect you are right about the age division, but would love to see some real numbers and studies about each side. Every study I have seen about the youth pushes your sentiment that "entire high schools are getting addicted", but when you look at the questions, they are typically very misleading and something along the lines of "have you ever tried a vape".

OTOH, being older, I have never met someone who vapes that didn't smoke before, and know several smokers who quit and switched over.