Don't be harsh, there must be a reason for his pent up anger and rage.
Maybe one of IL took his bat and ball and he just screamed and screamed but they wouldn't give it back.
It could be that after getting his first kiss under the mistletoe last Christmas his dog ran off and he now feels used and cheap.
Perhaps he realised Santa wasn't real.
These things are serious afflictions that could affect anybody at any time. He's got a huge chip on his shoulder and feels his best therapy is to share his pain and anguish with the world, he just wants to be heard, wants to be told he's somebody - so we should all sympathise, pat him on the head and go "there...there...who's a brave little soldier"