Ok, well I just revisited this scene again today. I gotta say, it is a little messed up how when asked, Ashe says "we leave at once." Maybe they did kinda turn their back on the kiltias.

but this is all in the midst of a really big phenomenon. "The Rozarrian Invasion" (a phrase you hear bout 50 times in the game!) could be any minute now. Vayne, a military genius, is all for it, and has just mobilized one of the biggest forces Ivalice's ever seen. You also just found out that the manufacted nethicite is much more dangerous than previously thought. And the scene preceding is Bergen explaining that there is a new Dynast-King - Vayne, and he's putting history back in the hands of man (i think this is why the place was wiped out - bergen proving that they do not fear the gods), plus they got psychos like bergen who infused his bones with nethicite.

so there's alot going on and ashe is the only one who can stop it. and at the same time, she's purely motivated by selfish reasons to avenge her husband, her father, and her stolen birthright.

and they do do something, they stay there for a short time to pay their respects, you see them standing outside the temple watching the kiltias pray. so i don't think it's all that bad. maybe ashe was a little cold, but that's her character.