Why would it be so important for someone to blame their rage on a dog?

He keeps insisting that my dog "starts" the fights. If I let the dog out, he screams, "What are you doing with that door." I said, "I'm using the door to go in and out." He was going on and on trying to DRAG out of me that I needed to use the door to let the dog out. When I wouldn't appease him, he shouted, "NO...it's the dog...you're doing that with the door to let the dog out." What is he TRYING to prove by stipulating that. He said, "That dog is ONE STEP away from causing a fight between us." The DOG does not start the fights...For some reason he NEEDS there to be a fight and he NEEDS it to be the DOG'S fault. WHY? He acts like there is something wrong with me when I protect my dog. Is he trying to prove that I love the dog more than him? What am I missing here.