I'd be okay (unhappy with the hypocrisy but okay) with Bruce hiding stuff from Dick when he was 12.
It is the whole not bothering to tell him 10+ years later. When he's passed the trauma stages and has seen things ALOT worse than his parent's death. At that point there is no denying that Dick can handle whatever horrible secrets there were about his parents death and Bruce has no right nor reason to keep it from him.