Your point about certain populations of drinkers being able to indulge without obvious adverse health outcomes is also applicable to users of vaporized nicotine. And again it is worth pointing out that alcohol is significantly more harmful than nicotine.
I would be curious to see any research that supports the idea that flavored vape products are primarily appealing to underage users. I suspect there aren't many teenagers opting for scotch as their drink of choice, but I am certain there are plenty of adults who prefer a rum punch, peach white claw, jameson and ginger ale, or a glass of wine (it's made from grape juice for god's sake, brazenly targeting the children!), etc.
Just to pick an obviously stupid example, I could chug a can of soda (or seltzer, if you prefer) in one go. It would contain around 2.2g of CO2. If you put that 2.2g of CO2 in my lungs, I would be dead. (Well, you would have to keep it there. It would at least be very painful.)
Or to pick another obviously stupid example, I could drink enough alcohol to kill myself. In most situations, I would vomit or pass out before I got to the fatal dose. But instead, I could give myself an alcohol enema and just die (which does happen, from time to time). So, delivery matters absolutely.
For the non-obvious examples we (at least) need data. If you are putting “high” concentrations of a chemical (for some appropriate definition of “high”) in your lungs you will want some good safety data. For ingestion we already have an FDA approval process. You may disagree with the methodology, but at least it’s there.
Hence dosage for injections/sublingual delivery is much lower than dosage for normal pills to swallow.
Should this apply to vodka and other liquors as well?