I think they are mean to him because he's the only one who can take the criticism and fight back with humour and wit and sarcasm, none of the other contestants have the ability to do that this season. Andy is far too fragile, Zendaya is only 16, etc... Without DL there is no drama, so, DL is the drama. It is crappy that he is the punching bag because it's horrible to see him getting suckerpunched week after week. That's not fair. So instead of getting mad, the fans get even. I really hate the writers on this show.