It's kind of insane the lengths the monsters will go to to not harm humans. If Aileen just told Bel, "We can't fight back because we'll be killed, or at least suffer severe casualties", I'd get that, but they instead have to take the moral high ground while their people are sold into slavery. They shouldn't just go burning random human towns, and of course killing innocent people and large scale war are bad, but they can't let that stop them from doing anything. And they're even buying back the enslaved monsters, instead of freeing them by force? This series has a really dumb perspective on this.