I think it's extremely hard to argue that kids tend to be emotionally immature and especially vicious in this regard. But considering the GP has admitted that in retrospect they find this action to be a dick move I think it's important not to try and generalize immature behavior to all of humanity.

The question of whether humans are more biased towards social or antisocial behavior[1] is a complex one that philosophy has struggled with for a long time without a clear consensus.

1. Often historically framed as whether humans are inherently good or evil.