>>541794069
>his unique condition
his condition pretty much only exists for no other purpose than to be the justification behind why the route is wrong, which is part of why people take issue with it: it's not that it's unjustifiable, it's that the narrative bands out of the way to screw you over for doing it.

The reason the Genocide route in Undertale works narratively is for a few reasons: You have to go out of the way to do it, removing any pretense of self-defense, and the Monsters are not obnoxious, evil, etc, and have more understandable motives, so they don't really deserve it.

But the main one is the emphasis on the player.
YOU are the reason everything goes to hell in the end.
You took an innocent child, and through your deliberate conscious actions, turned them into the vessel for a murderous, blood-crazed spirit that you created. Even the 'spirit' (Chara) is not inherently malicious or evil at first, but your choices wind up eventually turning it into a sociopath who only cares about bloodshed and power. It's both a representation of people who only care about having the strongest optimal character and what a player character who was made to do nothing but kill things and be the strongest would actually become like. It ends the route by (attempting to) kill the player, and after that point destroys the game unless you give in to it's demands or just delete the files

The reason it fails with SHRIFT is because before you've even done anything "Chara" already exists.
Instead of an empty vessel turned destroyer by your own choices, Kazuya's body is already inhabited by an evil abomination separate from yourself and it is very specifically the reason things are portrayed as bad if you go genocide. Due to the clumsy way it's handled it comes off less like the player being a bastard and more like "this path is understandable, but forbidden because you'll wake up cthulhu if you do it". Which doesn't have anywhere near the impact.