He was given one job, save the world. Who causes all of the problems in the world? Humans. No humans, no problems. Makes sense to me.
She was used by SHIELD/Hydra who never intended to help her, she's in constant pain and she's dying. She's just trying to survive.
His grandfather was cheated out of what's rightfully his, his mom was murdered and even when he tried to move on they tried to kill him. This was all done by the same family, I can't blame the guy from wanting revenge.