I've seen it used as broadly but very rarely - generally, "toxic environments" are ones where intentional malice is involved.
> people are forthright about how your well-being doesn't matter
Where in OP's post is this said? This would actually constitute malintent for me and elevate the situation to toxic but I can't find where this is said. It's possible given your experience that you know this happened, but I don't see it in the post itself.
My main issue is the use of "toxic" coupled with the post's advocacy for helping others recognize when they're in a toxic workplace. My concern is that anyone identifying with the general stress described could then accuse their coworkers/managers of manufacturing a toxic work environment. God forbid I have a meeting that someone else thought was unproductive and then accuses me of creating a toxic workplace.