Addressing the parts I chose to highlight with blue color, in order.
Yes, people are really wondering if vaping diacetyl is good for you or not. Given both the current evidence (with vapers) and the historical evidence (with smoking), the accurate indication and/or evidence tells us that inhaling diacetyl at the levels up for discussion is that it is not bad. So "not bad" that when compared to nicotine, it is more tame than that ingredient, and even that ingredient by us users who are arguably more in the know than all non-users (ever) is that inhaling nicotine is really not harmful, not bad. Compared to that, based on both current scientific evidence and anecdotal evidence (or what we users have experienced), inhaling diacetyl is more tame.
Thus, the only thing that right now the 'rather not inhale diacetyl' crowd has is to raise strong concern with long term usage. If this is a personal concern for this person, then who can reasonably argue against that and expect to 'win' the debate? Would be like anyone saying I'm deathly worried about inhaling PG, and is a personal concern I have, and so I'd rather avoid it. How might anyone convince me that I ought to inhale PG against my wishes?
I honestly hope with what I've written up to this point that all vapers are on the same page. If not, I think there is a debate to be had, one that ought to be had, and that it could get strongly worded if there is seriously a dispute to be had on anything I've written thus far.
Where it becomes another matter is beyond the personal concern and language of "but if YOU think there will be no consequences later in life, think again." That goes beyond personal concern and is either outright stating, you should be as concerned as I am or is strongly implying it.
The question has no way of answering itself in the short term for all involved. Literally no way. It will take long term data for whatever alleged harms (over the long term) to come to fruition in order for us to exercise a reasonable concern that all can observe / be made aware of. For otherwise, you have to return to what is said in rebuttal in first paragraph of this post. When anecdotal evidence returns information that suggests lots of vapers are being harmed specifically by inhaling diacetyl, then after all the years of smoking/inhaling it, and either nothing happening or very little and after the first 7+ years of humanity vaping it and very little happening, we now live in a (currently hypothetical) reality where in fact it is a problem for people to inhale this via vaping.
Plus there is a problem when there is this divide in the community and the side that is 'not okay inhaling diacetyl' tells the other side, "you think there will be no consequences in life." That is, IMO, as much of a problem as when mainstream articles go in direction of suggesting that (all) vapers think vaping is completely safe, and then the article notes one aspect of harm from vaping (i.e. batteries blow up) therefore, it is not perfectly safe. I'm pretty sure this is called straw man fallacy, but to elaborate on this point and be clear, you'll be hard pressed IMO to find this other side within the community claim that there is no consequences whatsoever. Instead, we are addressing people who have taken their personal concern for extreme danger and want that to be everyone else's concern and only filter the diacetyl data through that perspective. Short of that, and you (on the other side) must be saying it is totally harmless.
I continue to find that insulting.
And the reason we look at as people telling us what to do is because of how OP chose to word the first post of this thread, or if you'd like we could go look at any of the other 97 threads on this issue where someone, like as many as 30 people, are presenting the issue as very much in the vein of "the industry absolutely must change. Absolutely needs to go in direction of mandatory disclosure. Absolutely, we should all be sharing our concerns for endangerment with vendors." So, when some of you present it in vein like say
@Racehorse does where there is no demand to change the industry for the personal concern, that does at times get lost in the shuffle of yet another thread talking about what course the entire community should take to change the industry and rid it of this problem.
The one where we, a portion of the vaping community, have taken a personal concern with diacetyl in the market and inflated it to a full blown problem that "should be" everyone's concern.
When our actual opposition does this (with say formaldehyde, among many things I could've selected) we have tended to band together and fight back on such claims. This one has stuck. And yet, the evidence just isn't there for the inflated concern. When/if that changes, I'm sure I'll be made aware of it. Until then...