Possible Memoir Theme

Because I am writing about the cruelty towards these greyhounds (or animals in general), do you guys think that a theme could be about man's abuse of his natural power? I would probably emphasize the idea about how man, who is considered the "head" species of all life, is responsible for taking care of the life around him, but because of selfish motives, he, instead creates pain for others. I still need to craft the theme to make it better, but is this theme a good foundation for the memoir?