You really don't seem to know what you're talking about. All your references to Hawkes father prove that. Hawke had nothing against blood magic if you chose to play him that way. You need to replay the game because you clearly have mo idea.
Really - I have to play again to just prove that Hawke's father's situation was a situation that, in all and every variation, the Wardens made him do blood magic clearly against his will?
Chosing blood magic-friendly choices in the past in this case is irrelevant. Hawke's mother and father are fixed narrative situations where their role was intertwined with blood magic. You don't get to choose to agree or disagree with Quentin using blood magic against your mother, nor Hawke's father using blood magic. They happen and the way Hawke responds (diplomatic, sarcastic, aggressive) is always on the negative (in varying degrees). Towards Janeka and towards Larius. Towards the whole situation.
These two examples are not about my canon, nor your canon. Hawke's mother and father have two poignant, isolated situations where their role with blood magic happened because they just did. Why? Because that's how they were written.
On the side: If we want to talk about roleplaying, I had a Hawke who used blood magic. I had a Hawke who AGREED with Anders decisions, let alone romanced him. I played the blood-magic lover role many times in my playthroughs. To me, it feels like Hawke's parents' situation alone is still in sync with Hawke feeling so strongly to detest the stuff. I don't see it hypocritical, even if my Hawke clamored to use blood magic in DA2 at every turn, as blood magic isn't some one-dimensional thing that you can completely agree with in the game through roleplaying choices. (Sure, you can completely agree with Merrill for the demon and using blood magic, but the cause is just as important as the method. Merrill doesn't use blood magic for a nefarious purpose, and none of the options in DA2 where you can condone blood magic are cases where blood magic is used for a purpose like satisfying a demon army).
There are variations of blood magic - as a catalyst, as a sacrificial crutch, etc. And the methods that other people use it for. Not every action made through blood magic is the same, or produces the same result. Or is used in the same context. If your mother ends up dying because of someone using blood magic, that can still leave a bad taste in your mouth no matter how many times you slit your wrists.