Indeed, they are. However, there's the small matter of age and seniority. Is it not the prerogative of those who come first to do with life as they wish? There's no way to know just how old the oldest souls on Etheirys are. At least for those of us not possessing soul sight. If the souls were new, then they didn't know multiple lives as beast or man. Of course, it's fair to wonder how that might affect Zodiark's demeanor, unless he was never intended to give up Elidibus as his heart.
It seems to me that the Ancients respected the planet's natural law as much as possible, but in this instance of crisis they decided to exert their will over it. It appears bad from one point of view, but it's really not anymore of a perversion than Venat choosing not to die. In spite of Hyth saying that the ancients were mortal, it seems to me that with just a little initiative, they could functionally live forever. Generally by consuming others, body and/or soul.
Anyway, what seems to be conveniently forgotten is that the reason they wished to return the world to "paradise" was that their society had progressed beyond War, Famine, Disease, and even bereavement. It was the wish to deny all of the close calls and possible Armageddon of the past, before their peaceful society dominated the planet. I.E. Other Dead Ends. The fear that new life wouldn't be peaceful / do right.
Keep in mind that Hermes' sadness came from the fact that he didn't want to respect natural law as he didn't think his mentor should die. Even after an extremely long, fulfilling life. Even by choice. Then we view the fact that while sticklers disdained Venat's decision to not die, many others were all the more happy to continue suckling at her teat. It seems to me they were just like anyone else.
Live and let live, until push comes to shove, and it becomes, "You or me." "Them or us."