When are we supposed to stop fighting?

[Cleretic]

Summoning Zodiark is not a "natural ability" except in the loosest sense of the term, I would say.

Venat never said "paradise is wrong". She exhorted those who wanted to sacrifice to Zodiark to rebuild Amaurot with their own hands, which would indeed rely on those natural abilities, whether creation magic or simple crafting by using manipulator limbs like their own hands. This is putting aside whether Ancient society was perfect in the first place, since obviously Venat (and Hermes and Hesperos) disagree, but the principle holds true whether it is the ability to wield creation magic, or the ability to manipulate aether at all. It's the same as warning the people of the Fifth Astral Era not to keep sucking up huge amounts of aether from the environment; it's a shortcut, and the consequences for using that shortcut can be tragic.

Something else important to take into account is that Venat wasn't objecting to 'rebuilding but doing it wrong', but that the crowd didn't want to rebuild from disaster, they wanted to undo disaster.

Speaking literally, you can read this as just a semantic difference; they're standing in a ruined city, they want the city to not be ruined. But that's very much the wrong reading, it's very clear in the scene that they're coming from a fundamental angle of 'we want to go back to when this never happened'. They don't want to move on from suffering, they want to move backwards to the world where it hadn't reached them.