As someone who already functions in research psychology and observing human behaviour is a big part of what I do, I don’t think it’s not too far a stretch to say his innocence died with his parents and that this was a factor that led to his developing his ‘Batman personality.’
I do, however, think it heavily undermines the complexity of his character to say that nothing is left of Bruce Wayne and all that exists is Batman. That may be true in Frank Miller-land, but Batman is not who Bruce Wayne is at his core. He uses the image of Batman to induce fear in the criminals he encounters, but deep down, Bruce is a very human guy with real human emotions.
The fact that he does value family and human life is a huge part of why he actively works to preserve that. An outlet for his anger does certainly factor into how he operates as Batman, but it isn’t his only driving force for doing what he does on a daily basis. Anger is also not the only emotion Bruce experiences. He also experiences love, grief, and happiness as well.
If anger and Batman was all there was to Bruce Wayne, no one would be able to relate to his character at all. Anyone who seriously believes this is all Batman consists of has no real understanding of his character or the complexity of human personality.