I kinda get why. The empire hasn't really wronged him, and Manwol's actively looking to plunge the empire into a civil war which would lead to his subordinates/family getting killed. That being said, I can't imagine taking part in a genocide, realize it's fucked, and still be a lapdog for the military. It also doesn't help that the country next door's being run by an opportunistic scumbag that'll swoop in during/after everyone's weak.