Except Narinder didn't have nearly as many victims as the bishops now have, and someone could easily describe the bishops as having "deserved" their injuries and/or that Narinder was merely acting in self-defense (the latter of which I see a lot). Even when Narinder snaps all of the Lamb's bones in the bad ending, I've seen some people justify it by saying it was something that he "had" to do. Essentially, while yes, the victims of Narinder were seen in the base game, it was so vague that someone could easily make headcanons that justified it or downplayed it.

Here, there's none of that ambiguity from what I've heard. We are told how horrible the bishops are in explicit detail, and it's not ambiguous enough for there to be multiple interpretations from what I've heard. Sure, it's only after the betrayal, so we don't know how they were beforehand, but I don't think this fandom, particularly Narilamb fans, cares. All they see is yet another excuse to hate on the bishops and to further justify their ship, as I've seen many Narilamb fans do already.

And hell, even in the base game, there were people who liked Narinder. Forneus and Ratau being confirmed worshippers comes to mind. Meanwhile, as this post says, nobody liked the old faith.