I disagree. I'm thinking this was to show how the people talking the big game about taking care of business and killing anything that moans and craves flesh hesitate when its their loved one. The group had no sympathy for the farmer for him being unable to off all the people he knew loved and associated with before the uprising even tho he said they were just sick I think that was what he wanted to believe so he could hang onto the hope and justify keeping them around. I will say when the shooting was over I was waiting for the old man to break out the Clint Eastwood line "get off my lawn!"