I blame communism. I blame fascism. I blame psychotherapy. They--and a boatload of other well-intentioned ideologies that evolved during the mass-culture, industrialized, dehumanizing epoch of the late 19th and early 20th centuries--all posited the same fantasy. They all preached that human nature was perfectible, and that, therefore, evil could be overcome.
Quotes are taken from the research journals of Kyle Vanderburg.