Yeah, exactly. And honestly? I probably wouldn't even really mind a subplot of "There's a Kazuya who murders everyone and he becomes an interdimensional menace" - I mean, I probably wouldn't be that invested, but it wouldn't bother me either. But by the end almost every second sentence was about calling the players of Genocide runs pathetic, pawns, empty, cowardly etc. It was really weird, and if I wasn't a chronic completionist, I probably would've bailed the moment I realised I'd gone past the game and entered into the dev's tantrum. Only thing I hope is that he'd calmed down by the time he got around to Shrift 2, because the thing is, his art and the game itself checks every box for me so I don't want it to be ruined by something like this.
The thing that gets me about the dev's saltiness is that for the True Mercy run to be seen as moral, one needs to suspend a healthy amount of disbelief. As in, there's a kind of mindset one puts themselves in while playing a porn game like Shrift or MGQ (or at least I do) where you look past the fact that almost the entirety of the cast is made up of serial rapists/murderers since that part's only there to satisfy a kink. But if you actually want to address the issue of "Alright, is leaving these fuckers alive moral" rather than steering clear of the issue for the sake of the porn, then you've gotta be prepared for some people to bring IRL standards into the game, which sometimes include such hugely outlandish takes as "rapists are not cool" and "murder is bad".