I don’t think that Jason Todd being resurrected actually solved any of the guilt Batman felt for failing his second Robin. I think that’s one area that people instinctually and sympathetically view from Jason’s perspective; people want “yes his son died, but he’s back, now cope with the ways you failed as a father” when Jason dying wasn’t Bruce’s failing as a father. If anything, it was his failure as Batman.
Which is worse for Bruce. And means that even Jason being alive again can’t fill the whole he’s dug himself. Of “my boy, my baby, my son, and the child I was meant to protect” is dead and it’s because of my business. His journey for justice, his coping mechanism.
Jason being back and breaking the Bat-code at that, had to have destroyed him. His son is breathing again and doesn’t have any fight left besides to fight against what Bruce tried to avoid Jason ever needing; vengeance. Jason wants the world, for Gotham for the joker and for Bruce, to see what being disregarded does. He wants to make a name for himself that’s the opposite of what got him killed.
So not only has Bruce lost his son. In his perspective, he lost his son, and he failed his son.
