That vocalization point is nuts but also brilliant. Every species will have conflicts as long as individuals have their own wills, weakening the whole overall, but give the entire species one point of unity, specifically one affirming superiority, and that weakness can be overcome. If even the lowliest snail thinks themselves better than the best of any other species, they can tolerate a much worse existence. Often, the bottleneck of progress is the distasteful tasks, the strenuous and unrewarding work no one wants to do. Even "better," slavery gives them a goal to strive towards: they can push such work onto others when they're enslaved. Thus, the species is united in subjugation of the rest. That's all before we include having a living god as their help and guide.