@kwendy Orks' battle thralls, Lizardmen? Sure, maybe if they kill enough Orks.
Orks themselves? Eh, those guys seem to have been raised in quite a screwed up society compared to all others in the story. These guys have had no moral qualms about poisoning entire countries (that's the lands they plan to conquer) or watching their own tribesmen succumb to the insanity poison. They torture or kill their prisoners for fun. They kill each other for sport. They search for things to kill. While it's good to be an idealist, Vivian sounds pretty dumb in this chapter. I don't think she had much moral struggle about killing mad Wompa Loompas and pretty sure she resorted to killing the mad monkey man (the black one) too. These are the guys who caused every bad thing too happen in the story, her desire to defend herself and her orders to her men to do the same without killing them aren't just stupid, they're suicidal. She doesn't sound much better than those gnome guys, Orks already found them once but they think that the best course of action is to hide instead of uniting with others? Give me a break. Unless she finds a perfect 100%-successful way to ask them to go away, stop poisoning and killing others and also release all of their slaves, the alliance's plan to kill them until they decide it's not worth it to keep attacking and remove the mastermind behind them sounds much better.