Parent are the leader of their own child.Parent are the one who raise the kid up so they should be responsible for the dysfunction behavior of their child.As i notice there are many children with dysfunction and aggressive behavior.There many reason.1.Parents need to go to work and don't often take care their child 2.Some parents don't educate their child correctly or they themselve think it's ok to bully others.3.Family environment problem such as child abuse and divorce.While child abuse is on decline while divorce is increasing.So it seems many children suffer from it.But however no matter how much problem you have,you shouldn't express feeling through hurting other people.That's not an good outlet.And parent should teach this as well.
Bullying occurs because of ignorance, jealousy or even fear. A child can act entirely different in school than what you require of them at home. Bullying happens a lot because of peer pressure. Children don't want to disappoint their friends, they don't wan to be the black sheep. Many times they feel if they don't join in, they will also be bullied.