Kris being addressed with They/Them pronouns does not necessarily mean they’re non-binary. Being a silent protagonist doesn’t mean they’re autistic or whatnot either. Stop this nonsense right this instant. You can headcanon any little thing you want, but so can everyone else.
Yes, you can scream about representation or erasure, but I won’t listen. I don’t care. This behavior is a large part of why the Undertale Fandom got such a bad representation. We don’t need people dragging this melodrama back from the dead.
It boils down to this.
People have every right to interpret these characters however they wish. You don’t have the right to force your interpretation onto others. That’s all. So if you can’t live with that, too bad. This is the internet, you’re going to be exposed to different opinions. If that offends you then you should probably just go.