The public perception of bullying is that bullies are acting out to cover their own fears. They may indeed be afraid, but accepting this as a reason makes bullies sound like victims of their fears -- like we're supposed to feel sorry for them and not hold them responsible for their abusive actions.
The issue is not whether bullies are afraid. Bullies bully other people to feel powerful around them and to feel power over them. Bullies start out feeling like zeroes, like nobodies. When they intimidate, threaten or hurt someone else, then they feel like somebody. The key is the feeling of power.
Read The Truth About Bullies