I Wish People Would Realize How Their Actions Hurt Others

Worked my job as summer camp leader today. Eight year old fellow went around screaming "I hate you!" and punching me, and literally being as disrespectful as possible to all the other students, for no probable reason. His mom had him home for lunch.

He's eight. just before his mom came, I managed to calm him down a tiny bit. We went outside, and I managed to talk with him for a minute. Here's how our conversation went.
Me: "Why are you so disrespectful to everyone?"
Him: "Because I don't know them."
Me: "But you were disrespectful to me too. You know me."
Him: "No I don't."
Me: "Why not? You know my name, and even how old I am. We were buddies the first day of camp."
Him: ...
Me: "What about the other people here? Even if you don't know them, don't you think it hurts them to yell and hit them?"
Him: "I don't care."

More than anything else, this conversation made me sad. Someone who doesn't care at age eight. There are plenty of teens who don't give a darn about almost anything, but this...?
I hope he grows into a mature person.