What the heck is wrong with you? This is a five year old child. All the reports I read stated he was in trouble for being disruptive (which is a hugely subjective term) and spitting on another child. That is not thug behavior.
Frankly if a teacher and principal cannot find an alternative means of discipline for such minor offenses I think they should not be dealing with younger children.
He has been regularly assaulting other children.