Defender Ogre Jailbreaker can attack as though it didn't have defender as long as you control a Gate.
It took three years for it to occur to him to use the chain as a weapon, but once it did, he made up for lost time.
Official Rulings for Ogre Jailbreaker
10/1/2012 : Defender only matters when Ogre Jailbreaker could be declared as an attacking creature. If Ogre Jailbreaker is already attacking, losing control of your only Gate won't cause Ogre Jailbreaker to leave combat.