Is superiority a necessary aspect of cruelty?

Chapman & Huffman argue that humans inflict cruelty without apparent concern because of their categorization of the victims as inferior. The supposed inferiority of non-human animals can be argued against on the basis of documentation and analysis of behaviour. Humans continue to inflict cruelty on their own and other species. It is not obvious that a sense of superiority is a necessary aspect of cruel behaviour. Nor is it obvious that further enlightenment regarding the cognitive status of non-humans will diminish cruelty