Mack isn’t entirely evil or unfeeling. This photo in particular suggests that Mack loves Ivan, or at least did when Ivan was little, and tried to do the best he could for him. Though Ivan has spoken fondly about his time living like a person with Mack, it's significant that here, he notes that he doesn’t look like a gorilla in the photo. Now, Ivan seems more connected to the fact that he’s a gorilla, and he sees the way that Mack raised him as harmful and unintentionally cruel.