If someone ends up with lung damage and they wonder why they had no clue about the dangers, what should we tell them?
After reading thru the thread from what my previous post quoted to where this current post appears, the thing I feel your position ignores is that some people do want to inhale diketones. I think you cannot fathom that, and I honestly do not know why you cannot. Nicotine is a known toxin. I think every vaper knows this, but I don't know that every vaper knows this. Therefore, we probably all agree that vapers who vape nic want to be vaping it, despite the risk, and yet there could conceivably be people who don't know the risk and/or only understand the risk as being "might lead to addiction for life."
Nicotine has benefits, and is IMO mostly the reason why people choose to inhale it, rather than some claim of "I'm addicted, I can't control myself from wanting more product with nicotine in it." Same goes with alcohol, coffee/soda, and really most things (arguably everything that is ingested). Likewise, with flavors, there is the benefit that diketones provide. People will then say, well we don't need it. But that's true with most everything you can name. You don't need caffein in coffee or soda for it to taste about the same, and could put in other ingredients if "extra energy" is what you are after. It's not like using caffeine habitually is risk free.
Thus, as I harp on, we have very little reason to be concerned with what inhaling diketones will do to vapers, given what we know about a) our history of inhaling them (for decades) via smoking and b) how long vaping has been around and there aren't known cases of damage to vaper's lungs.
So, even with a question like the one you posed above, it ABSOLUTELY HAS TO be worded as "if someone ends up with lung damage" cause you can't sit here and lay claim to any known cases where it has occurred. This tells me you aren't so right about the side you are on.
But to answer your question, I'd ask them what they thought might happen by habitually inhaling anything. IMO, that's not being cold, but being realistic with how to best go forward with where they are. I would be curious about knowing what they do know about vaping ingredients, but might not ask them. My not knowing that information would not make me have less sympathy for their current (hypothetical) circumstance, but it would provide me with some semi-pertinent information for how effective treatment could be in their case. IOW, it is plausible that if given a physical substance for treatment, they could be clueless about the dangers of that substance, for surely whatever they take would not be risk free, and they may be of mindset of not seeking out the data regarding what is known about that substance.
All I could do is to accept responsibility for the part I played in that, the part we all play when we say, "go ahead, vape diketones".
IMO, the role one like you could, very easily, play is to let them know that there are vendors that exist right now who claim to have product tested, claim to display actual test results, and claim to be diketone free. I say "claim" because I stand by my position that unless person does their own testing, they'll never KNOW for sure. They just won't. They might think they do. They don't.
But I'd be real careful with that sort of position for vaping could plausibly cause damage to a person's lungs and IMO, it would seem very likely if someone is going to vape daily for decades. What that amount of damage will be is impossible to determine. But if you think vaping diketone free amounts to a "get out of damaged lungs jail, for free" card, well then IMO, you've arrived at this discussion clueless.