The Amaurotines were incapable of dealing with Meteion directly because of their aether, so that wasn't actually relevant to the discussion.

The question was, having summoned Zodiark and having averted the crisis for the time being, whether it was necessary to still keep sacrificing souls to Him in order to build their perfect paradise. Having already seen several tangible examples of societies that went that exact same route, they might as well have renamed Him Ra-la and be done with it.