It appears to be difficult for young children to disentangle aggression and pro-social behavior when they are combined, as is common in the superhero genre.
I've been consistent on this. Young children, in the absence of direct experience, believe what they see. They believe these behaviors are 'legitimate' and/or appropriate, unless specifically given context by parents. Kids don't listen - they follow what you do. How you behave. Those are the characteristics that stick, consciously and subconsciously.
Worrisome is the fact that superheroes have gotten a lot darker. Our parents were worried about the effects of the "Batman" series, the first campy one. Anyone else remember that? Along with "sit at least five feet away from the television, or you'll go blind."