I don't know how anyone who works for JUUL Labs can sleep at night.
That doesn't mean that vaping is harmfree.
But your Wikipedia link tends to say that nicotine (other than being addictive) is mostly not harmful.
Here's a question that I don't see answered in this page though: I'm a non-smoker and asthma patient (was diagnosed at age 7, the cause is most likely second-hand smoke from my father), so I always stay clear of smokers and don't let anyone smoke indoors while I'm around. What is a reasonable policy to assume wrt vaping? Do we have any evidence regarding second-hand vaping? I'm not particularly worried about getting addicted that way, but about whether the smoke from an e-cigarette can be harmful to me as an asthma patient (or to others).
(And while we're at it: What about Marlboro's Iqos? I stood next to someone using one of these a few weeks ago and the reduction in second-hand smoke and stench is remarkable.)
The biggest issue with smoking is particulate getting into the lungs. Firemen who spend their whole careers breathing non-tobacco smoke have rates of heart disease and cancer similar to regular cigarette smokers.
This of course regards only nicotine, and not all the other chemicals associated with any kind of smoking/vaping.
If people need to sleep well at night (and many don't care), this reasoning is duplicitous. It'd be better to build a service that helps with smoking/nicotine cessation.