His words had a strange effect upon me. I compassionated
He has all the reason to lament the Romantics of a human society he can't be allowed in. The human mind is irrational and is only justifying for itself, or at least that is what the creature sees. His negative view on the tenets of human rationality turned him to the monster, the animal, the logicless creature that he showed himself to be at times.
Mary Shelley wrote Frankenstein to display the characteristics of Modern Rationalism and Romanticism. She did not lean towards one belief. It was popular because of this representation of the contrast, yet steady convergence of the two beliefs.