rough drafting it here but i think Batman has a special connection to the concept of child sidekicks in a way that defies modern feelings about child soldiers because he was the child who lost everything and felt he needed to make a change in the world but was denied the agency and choice to do anything. child Bruce would have fit right in with any of the Robins if he'd had a Batman and it's the fact that he didn't that ultimately drives him to extend the choice he never got. it was never about soldiers or "refusing to protect the children from themselves," it is, within the acceptable morality of the genre, respecting a child's personhood and ability to make decisions for themselves and giving them opportunities their adult never had. it's why you can't take the Robins away from Batman without significantly changing the character, because Batman was born from child Bruce's most heartfelt wish to be able to DO something about all the injustice in the world and so to deny other children that is to deny himself
and on the topic of protecting the children, not being a child vigilante did not save Bruce from tragedy. and not being a child vigilante very famously did not make Bruce more mentally stable. there is obviously his parents murder but if you pick up any comic on his childhood things were really bad for him, his school headmaster turned into a demon, he watched his friends die in front of him, he faced some level of neglect or abuse from his parents depending on the comic. pretending it's just the vigilantism that is the cause of all suffering in these kids denies their backstories and is...incredibly naive thinking on people's ability to otherwise protect children. vigilantism/heroing is a trade off, more exposure to pain and injustice for the ability to interfere with and stop it. and some people need that trade off in order to keep going.
