I think the situation from that article is exaggerated. Whether the lionfish came at him or not does not mean he wasn't careless. Whenever I'm working in a tank with lionfish I always make a major effort to keep an eye on them and/or to keep something between my hands and them.
As for the dying in within an hour, it's clear that the doctors had no idea about lionfish venom. I find a hard time believing that they could go from that to making prognostic decisions that quickly.
From the quotes I saw, the vet seemed shocked that it was even possible to get stung by a lionfish. Unless you're allergic to the venom, or already have a serious chronic medical condition, death from a lionfish sting is unlikely. The symptoms he described are not typical for anaphylaxis (allergy).
It's this sort of embellished reporting that leads to animals being branded as dangerous and being banned.
Dave