Then the owner of the dog is responsible. If your imagination is correct, then this poor man is attacked by these dogs often and he finally got fed up.
Plug this into your imagination: if the man walked by the dogs every day and poked them with a stick through a fence, and one day the fence was open, would you blame the dogs for getting fed up with the daily abuse and attacking him?
Right. It could be the man has been hitting on one of the daughters of the dog owner and got her pregnant. The dog owner found out about it and threatened the man. The man started carrying a gun when he walks fearing the dog owner might come after him with a gun. The dog owner thought up a brilliant plan to go after him with his dogs. He looked out his window and saw the man go for a walk and set the dogs loose. The dog owner also voted for Obama. Yeah that's the ticket