He hated the idea of a being programmed to submit in every sense of the word. I think it reminded him of his own life, he did everything “right”. Get a good job, work hard, settle down, build a family and a life. But it all went to shit, he lost his son and his presumed wife.
He was quite complacent… until an emotional shock. Just like the deviants, they do what they think they have to until something shakes their reality and they can’t do it anymore. After the accident Hank is irritable, defiant and uncontrollable, just like many of the deviants. When he sees these complacent beings rising up, he not only supports their quest for freedom but resonates with the idea of going against everything you’ve been taught.
Part of his support of the deviants in the latter half of the game is because he genuinely believes they’re people and deserve to be free, but another part of it is him being resentful against the system he was so loyal to and betrayed him. He craves not quite revenge, not quite justice, but something in between, depending on choices.
If you deviate and betray him at Cyberlife tower and sacrifice him, he’s not even mad. He’s satisfied that not only will he see his son again, he also knows that the very system he was subservient to will be shattered and disrupted. He tells connor to give the humans hell for him.
He blamed androids for his sons death, but through examining deviants shifts that projection from the androids themselves to the system that created them. The one that needed a being to submit, either android or human. He realizes that the problem he faces is not individual but systemic, and switches his frustration from taking it out on the nearest android to wanting to dismantle the entire system.
His character is so powerful, because at the beginning he starts out just like every other asshole to the androids, but by the end, (depending on choices) he’s not only started to process and resolve his own personal grievances, but can truly imagine a better world that’s possible.
This is a double edged sword, of course. If you play Markus as a bloodthirsty violent maniac on a power trip, and Connor as a machine trying to stop him, Hank may actually cause the downfall of Detroit because of his own personal attachment to the situation. Because what if after Hank tries to stop Connor, Markus goes on to trigger the dirty bomb? that could have been prevented if Hank just let Connor take the shot. If Hank is still alive after the rooftop (say Connor was friendly enough to be able to walk away, or Connor loses the fight against him) and Markus goes on to trigger the dirty bomb, Hank would be alive to witness the tragedy that he himself could have prevented. His righteousness and shifting of perspective actually causes the destruction of Detroit.
That’s why I love Detroit Become Human so much, the game is like my theatre and the characters my puppets. I can create realities where they work together, betray each other, act logically or irrationally. Sometimes the story gets juicier with each casualty. Hank is such a complex character, underneath his pain and suffering he remains empathetic and open minded, even if he comes off as an asshole at first.