Endwalker's message (spoilers!)

[Theodric]

They absolutely brought the Final Days upon themselves.

I disagree. Hermes being unable to handle death/follow established protocols and Venat adopting a defeatist world view is why the Final Days happened. I'm also not sure why Hermes and Venat doing shady things means that the Ancients as a whole are responsible for their actions and apparently deserving of death? The Ancients as a whole were not callous and cruel. They sought to benefit the Star and took care in ensuring that creations were not dangerous. Hermes could not understand that some creatures are simply incapable of living side by side with civilised beings - much in the same way as how some foolish individuals will approach a wild animal and then claim to be surprised when it starts attacking and devouring them.

It's pretty clear to me that the message of Shadowbringers was a clash of like wills between Emet-Selch and the Warrior of Darkness. Both sides were carrying the burden of doing whatever was required in order to defend their people - and improve their situation. Which is an reasonable expectation. It makes sense for the Sundered to not want to roll over and die for the sake of the Unsundered...but equally, it makes perfect sense for the Unsundered to not want to roll over and die for the sake of the Sundered.

Endwalker follows through on that by confirming that Venat was far too hasty to pull the trigger and never gave her people a fair chance due to being an unhinged saboteur and abusive mother figure with delusions of godhood. In the end, as Meteion confirms, the answer to Hermes' question lay on the Star all along. We know the Ancients were capable of friendship and exploration, so nothing the Sundered did is anything that the Ancients themselves could not have done had they been given the possibility.

I rather suspect that Venat being very pretty will also factor into the eagerness for many to rush to defend her, though. Much in the same way as how Meteion has her hand held because she took the form of a little girl...whereas many of the male antagonists, no matter how sympathetic, simply end up getting a stoic nod or frown. Funny, that!