There's no reason to ever justify bullying, even if one bully is being bullied by another. This reminds me of a situation I faced in one of my middle school classrooms. I had both of the biggest 8th grade bullies--male and female--in the same class, and they both tried to exert their particular power over others in the classroom. So, I placed them side-by-side in their connecting desks. The girl soon discovered that she could have her way with the boy, since he displayed some chivalric behavior by refusing to hit her back. He was soon humiliated, since every time my back was turned she took advantage of him, much to the class's satisfaction. His bullying in the classroom ended, and the girl soon realized the reason I had put them together. I had a little talk with her, told her that the boy--deep down--had some gentlemanly qualities and wouldn't hit her back because she was a girl, and explained that I couldn't allow her to take advantage of him in the classroom. They soon became buddies, and I had no more problems with either of them--though I'm sure they returned to their old ways once outside my classroom.