I define the story of Frankenstein and his creation as possibly reflecting criticism of how slaves were treated. Frankenstein knew the body parts of the corpses were dead, yet he still knew he could bring them back to life. They considered slaves as not humans, yet they had them doing human labor. Something you could not get any other living thing to do the way a HUMAN would understand to do. Calling slaves unhuman was their way of offsetting the guilt and the inhumanness they knew they were doing to slaves. In the book it explained that the monster learned how to read, write, and communicate. With that came the development of thoughts, emotions, and desires for the monster. This explains why slave masters did not want slaves to read and write because they did not want them to be able to think and form opinions for themselves like thoughts of liberation and freedom.
The people in the book did not want to bother with the monster because of the way he looked. It reflects the discrimination slaves endured because of their skin color and being called non-human. The blind character in the book spoke with the monster because he had nothing to judge him by, being that he could not see. The monsters killing reflect the pain that slaves went through. Because of how the author was described as someone who opposed slavery, the book reflects how people mistreated and degraded other humans (slaves) for the selfish benefit of themselves and for the fact of just being evil.