I don't think they even understand their own morality, to be honest. Mallach himself mentions how they're (maybe) only able to perceive the world from a certain, directed viewpoint thanks to the way they achieved sapience. Nareva also discusses how discovering new things about herself is one of the only things that keeps her going.I think it may be fair to say we can't comprehend the morality of the seven. Or at least that judging them from the perspective of a mere mortal isn't fair. They developed emotions based off eating mortals, but they were eldritch horrors fueled by hunger that exist between the worlds first and foremost. Those experiences would have shaped them in incomprehensible ways. And they didn't stop being wraiths (I'm pretty sure) just because they achieved divinity. They're still not exactly like the the people in the worlds. When judging them, we gotta not be distracted by the boobs and realize that the boobs are an illusion to hide the gnawing tentacles of unfathomable terror. Mmmmmmmmm, tentacles. Okay we also gotta avoid being distracted by tentacles.
Speaking of hyper-focused, directed viewpoints, demons seem to be pretty similar to wraiths in that way. Most demons seem to really like sex, but they also tend to have a secondary interest they're just as obsessed with. Like Kas and science/magic, and that one shop demon and capitalism. Meanwhile, wraiths are hyper-focused on souls, and in the seven's case they're also focused on whatever their portfolio happens to be.
We know souls can be used as a consumable resource, but does the lack of a soul do something to, idk, narrow a creatures world-view?
(Like your new profile pic, btw)