Endwalker's message (spoilers!)

[Lauront]

How so? The final days wasn’t really their own doing, and they were suffering trying to bring back their loved ones. As we know, a primal being slayed doesn’t untemper someone so presumably the sundered ascians are still tempered. If you mean the souls within him then yes but i meant moreso the ancients as a whole.

It's also nowhere confirmed that the ancients within Zodiark were tempered. That is specific to the summoners, and the lore directly before entering Ragnarok further undermines such claims as meaningful anyway. As for the ancients as a collective being to blame for the actions of one madman and his bird waifu? That's about as logical as blaming the entirety of the sundered if the Black Rose were to run rampant and consume the planet. Makes zero sense.

[Theodric]

It's also nowhere confirmed that the ancients within Zodiark were tempered. That is specific to the summoners, and the lore directly before entering Ragnarok further undermines such claims as meaningful anyway. As for the ancients as a collective being to blame for the actions of one madman and his bird waifu? That's about as logical as blaming the entirety of the sundered if the Black Rose were to run rampant and consume the planet. Makes zero sense.

Yep. Plus Tempering in itself has been shown to be very flexible. In some cases, it alters the mind and body completely. In others, it has very little or no influence over the actions of the individual. For example, Emet-Selch brought Y'shtola back from the dead which he would not have done if he was truly unable to do anything but work towards the restoration of Zodiark. Which, in itself, was simply a means to an end - Zodiark was but the method required to restore the Source to its original state.