Yeah, the way in which the protagonists react to killing people they know have been given a raw deal is pretty unsettling. It's why I don't consider any of them to be heroes no matter how often the game tries to pretend otherwise. Heroes have consistent morals. The Scions do not. Heroes seek to do whatever it takes to protect their loved ones, no matter how dirty and bloody their hands might get. The Scions barely bat an eyelid in response to the revelation that Minfilia's death was entirely avoidable when shown and told that Hydaelyn wasn't as weak as she claimed and had secret power reserves to 'test' the Warrior of Light.

I'm not sure how fighting Hydaelyn is meant to be a test, especially not when there's a battle in Elpis where the Warrior of Light defeats the vastly more powerful Unsundered version of Venat. To say nothing of the many victories that Venat has seen the WoL secure...or that Venat, as a Primal, isn't a great test to begin with when her 'blessing' and the Echo specifically counter Primals in general.