I don't think of Broly as evil! Like don't get me wrong here, he is beyond and above insane with anger! He seems to bear this insurmountable hatred towards the sayian race, but ironically he seems to have aimed that amount of hate towards anything and everything that moves but most of all Goku! In many respects he doesn't even seem to know anything else but this, he seems calm almost detached when he is not being a complete psychopath almost like he doesn't want to do this, or more like he has to do destroy everything to simply justify his own existence! In many ways he is like the Saiyan equivalent of Buu! A demon forged out of pure hatred!