…And then, even before Buttman, there were pioneering '80’s pornstresses like Elle Rio.
Not that it really matters, but I think it worth pointing out that there is a (little known) third option.
I think it might be specifically the influence of the “Mike in Brazil” series and its ilk.
It’s not fiction. There are a few studios in Brazil that do niche fetish stuff for the export market–the most infamous being MFX Video, the studio that did “Hungry Bitches” which is better known to Americans as “2 Girls 1 Cup”-- and your example happens to be one of those niches.
Anyway, to the OP, I’d say that “Brazilian” in reference to porn tends to refer to the actual source of the video, which is considered an exotic alternative to the usual American and Eastern Euro sources. That it happens to often be ass worship or extreme fetish (scat/puke/etc.) is mere coincidence; the few “Brazilian” videos in my collection happen to be rather vanilla lesbian videos… that just happen to be filmed in Brazil.