I doubt the author is generating sympathy for the character in the interest of excusing their actions. Maybe an explanation, perhaps even a springboard for redemption. The dog seems to be dealing some real damage to her. If this all her delusion, a dream, it may be roundabout introspection that will cause her change one way or another. Either becoming less of a heel or more likely double down and become an even worse abuser. That she's so arrogant she'll laugh at a chance to become a better person.