Sure. But I am responding to you, not that guy upthread.

Your implied claim, as I read it, is that "opioid-ness" is "why fentanyl kills," and there's nothing special going on because we had a bunch of deaths from licit opioids in the early 2000s. But I think that there's actually something special about illicit fentanyl in particular, as opposed to regulated opioids, and dose inconsistency is one plausible difference.

Anyway, you could just share what your thoughts are more explicitly, and that would be interesting and maybe harder to misunderstand.