Have you noticed it's always the boys that hate him, the answer to that is pure jealousy. They envy him. His looks, fame, popularity with the female audience. It's not rocket science to figure that out. :)
Cause they just want to bother you being a fan of him....you either are a Justin fan and know all of his songs and love him or you try to be cool and make fun of the people who are...it's kind of like Dreams vs Jealousy. People just are cruel to him and I always stick up for him(: keep on beliebing!