Because the idea of Kris working with the main villain because he's simping over the teenage BPD bitch who molested him when he was 10 is just the right kind of fucked up.
It is kind of annoying how much the fandom has severely misinterprets sans' personality in fanworks, he's either pissing and shitting himself in pure rage and is going to FUCKING KILL YOU for killing his bro, or takes nothing seriously at all and makes fart jokes every chance he gets. Really he's a lot closer to actual stoicism given his predicament. He's aware of different timelines and how they go, and yet does he freak out or breakdown over it? No, he just accepts it as it is, maybe he's fortunate in one timeline, maybe not and accepts that there are sans-es out there living a better life. It's only when he's pushed to his absolute limit on "standing by/judging" does he really act on stopping the player from causing any more harm in the world.
I'd say this one animation is about as close as it gets to properly portraying who sans is as a character.
I get the fanbase misinterprets almost all the characters from UT/DR for various reasons, but sans is probably the most egregious since all his nuance is stripped away leaving him to be overly emotional or a reddit-chungus jokester.
Sebastian Wolff is a lawyer representing Materia Collective, the record label that manages Toby Fox's music. As a public figure within UT/DR he became infamous for being harsh about copyright enforcement for a franchise that's usually lax and permissive with fanworks, and for being overtly dismissive whenever fan musicians tried to communicate with him about copyright issues.
Recently, some jeet at YouTube no-no-touched the Copyright System, which caused the revenue of multiple fan musicians to immediately tank. When asked about it on Xitter he responded in his usual fashion, claiming that nothing had changed and that "no one is in trouble." This caused a community outcry, with some questioning Sneaky Tony himself for working with someone so comically corporate. Apparently it was bad enough that they kicked Wolff out of his public-facing position, and Toby had to get off Bluesky and momentarily come back to Xitter to clear the air.
Woody Theory is NOT real, there is no "Friend Inside" Kris, you are delusional for thinking a 30 year old film/tumblr shitpost would make its way into a trooncore game and you should take your meds NOW!