"he was literally executing an incredibly heinous norm of his boss, and they're all slavers and torturers"
These standards only applies if the villain is part of a corrupt system. Generally, given they are part of a specific system with certain morals, they don't commit actions that are beyond the basic heinous standard and meet "the norm", regardless of how heinous this norm might be. That's why minions or simple servants of greater villains usually never qualify.
However, a villain may qualify if:
They started said system, and thus meet every criteria (e.g. Poppy Adams).
They commit atrocious actions that go far beyond the norm of the system they exist within, which can also prove that they would commit such atrocities even if they weren't a part of said system. Jerome Valeska of Gotham is an example of this because, even as a member of the Maniax, he committed the worst atrocities, to the point that their leader unexpectedly betrayed him."
So first: We don't know who started this entire norm, as awful as it may be. Also, his description "Fat/Obese/Green Leader" is a speculation with no in-series evidence.
Two: If they all enslave even children and subject anyone to torture, how are they supposed to stand out from other villains from their own cult?
Three: The old entry literally described all of them as an example of this. All you see there is a group of guards:
Four: They aren't Played for Laughs at all. Even my summary lists "the group rule" of that page:
Last: There is a tweaked entry to describe the case closer (of the other ATT):
While all the Zeref cultists are nasty, no one made so much damage as the fat leader. He took part of the slaughter of every adult in the village Erza were in and kidnapped children, so he could enslave them. Along with his partner, he forced thousands of captives to build the Tower Of Heaven. They employed even children (among which, Jellal and Erza) to do this work, starving them almost to death, punishing and killing them over the most insignificant slight; and they weren't above Cold-Blooded Torture as well - it was because of a particularly brutal beating from them that Erza lost one of her eyes (the eye was later replaced with an artificial one). Killing them both was obviously Jellal's making as evil, but they had it coming.
Okay, but seeing it not a big thing, I left it.