I'm planning to play the demon path in my next playthrough so I'll see how it goes, but I will say in her defence, you don't explicitly start walking that mythic path until after you've been made commander and retake Drezen. At which point you've already shown yourself as possessing supernatural power, doing things no mortal could do in service to the crusades and you're really effective. A conflict to remove you would further strain resources in a way that would only further hurt the war effort after a point where it's been shown that they can't simply sit and rely on the wardstones indefinitely anymore. I admit that it's not a GREAT rationale, but I think it's a decent explanation.
