Comparing smoking to vaping, is like comparing raisins to watermelons. They operate by two totally different mechanisms. Smoking is much more offensive to non-smokers because the burning of tobacco (marijuana, etc.) is not inhaled by the user primarily but is lost to the environment by a ratio of more than ten to one, whereas the "smoke" produced by the vaper, is only what they draw into their lungs -- and then blow into the air, which is actually a miniscule amount, and that is why it can hardly be detected.
So even if vaping is as harmful as smoking, it has much less of an impact on the non-smokers (and environment), which rightly, should be the primary concern, because it is the innocent we want to protect first, and not those bent on exercising personal choice -- whether that is BASE jumping, climbing Mt. Everest, drinking, overeating, not exercising, blowing through stop signs on a bike, etc.
The just society is to protect the innocent, and not the guilty as though they are the innocent, and the victims of society -- as has come to be the fashion among the nondiscriminating. And that is the big problem in any society -- of not making the valid discrimantions from the arbitrary, and then passing laws that only permit the arbitrary -- as in many "progressive" states.
Anybody who has ever visited a chain-smoker's residence, knows that the walls and furnishings of that environment are coated with brown, sticky tar and residue -- which is also going on in the lungs of the smoker, impacting health tremendously in that fashion -- rendering the debate on whether nicotine itself is harmful, as a much smaller risk.
That's why the argument that smoking marijuana having no impact because THC itself is not harmful or even medicinal, has to weigh the process of smoking itself as a huge impact -- that is largely ignored by the usually same "progressives." In fact, one notes that the resin and tar produced by marijuana, is considerably more, by the very nature of the subtance.
The base of e-juices is glycerin, which actually has favorable effects -- usually as the base for most cosmetics, topicals, theatrical effects (to produce "smoke"), which also leaves a thin film in most air purifiers, which is a lot less sticky and thick than the residue produced from smoking.
Unfortunately, a lot of people expressing opinions and notions comparing smoking to vaping, haven't given it any thought or investigation at all -- in any real world experience and experiment, which is the greatest danger of all.