People have been learning about being fed to the lions and crucified forever from a very early age. While I agree that it would be nice if we all agreed to let children be children, but violence is part of our world and has been for millennia. It is only a very small part of the world population that is so sheltered as to not encounter violence from the time they were able to walk. Hate, judgement and cruelty are part of the human experience, sad to say, and inexperience or innocence are no protection.
I just wish that the delivery of the information about violence includes a balancing compassionate approach on how to cope with the negative.