To preface this, I already know the abridged version of what all happens in the story, and I also know what the internet thinks of Ava. So I wanted to play it for myself and see if I can find these so called unforgivable sins the character does. I'm up to Eden-9 (rescue Jakobs planet, right after Maya gets merced), and I haven't really seen anything Ava does as offensively bad yet, and I feel everyone hasn't done anything out of character.
So essentially from what I've played so far, she hasn't really done anything deserving of hate yet.
It's less about the taunting and more about the twisted hero complex he has that makes him well written imo. He does completely deranged stuff like making his own daughter a lab experiement but when you put an end to her suffering he behaves how you'd expect a proper father to when his daughter is killed.
Then the presequel shows his descent into madness, and how he actually was a "hero" at one point, but gave into his bloodlust through the course of the story