What is the meaning of the quotation "If you have your lower to contend with,we have our lower classes"

This quote by Pilkington addresses the fact that the line drawn between humans and animals is virtually nonexistent. In context, Pilkington is verbally exposing that both humans and animals having a working class, thus, both systems are based upon a class system. The animals did not gain equality in the rebellion, they just created more of the same within their own animal government.