Uh, the Ancients literally caused the Final Days, and then they sacrificed half their population to try and fix their mistake by creating Zodiark. Also, the Final Days turned most of Etheirys into a barren wasteland. He didn't actually fix the problem. They had to sacrifice another half of the population to restore life to the planet which is what Venat and her supporters opposed, which is why she caused the Sundering. And I'm not sure you can call what Venat did genocide. The Sundering fragmented the remaining Ancients into mortal, weaker parts that led to the myriad races and peoples. So sure, they weren't the perfect, immortal beings they were before, but it led to more life on Etheirys and the reflections, while limiting the power of the remaining Ancients who thought mass sacrifice was a good strategy.
And I realize we've gone very off topic from 6.55. I agree with the OP that it seems odd that we're going to help Wuk Lamat without knowing anything yet. Would have made more sense for her to explain what she wants, and ask us to come to Tural and see for ourselves, and then decide whether to grant her our help.
Also didn't like the shady Thancred/Urianger scene. They know better!