According to a different source, this question refers to the story "The Red Bow" by George Saunders. In this story, we learn that a little girl called Emily was killed by a rabid dog. Because of this, Emily's family decides to go on a campaign to kill all cats and dogs in the area, in order to ensure that the tragedy is not repeated.
I believe grief was the main motivation for these actions. Emily's family was initially driven to kill the dogs that were actually sick. However, once this was done, their grief made them unable to stop. This helped ease their pain because it ensured that such a tragedy was never repeated. It allowed them to think that Emily's death had perhaps served some purpose, or brought along some good.
