I think that you're supposed to take away some lessons about the impact of early environment on cognitive development. But all that is overshadowed by the horror of how human beings treat each other, and especially the casually malevolent way in which they treat children. It puts one's mind in accord with Freud's conclusion that "most human beings are trash."
"I do not break my head very much about good and evil, but I have found little that is 'good' about human beings on the whole. In my experience most of them are trash, no matter whether they publicly subscribe to this or that ethical doctrine or to none at all. That is something that you cannot say aloud, or perhaps even think, though your experiences of life can hardly have been different from mine. If we are to talk of ethics, I subscribe to a high ideal from which most of the human beings I have come across depart most lamentably."
-- Letter to Oskar Pfister, a Christian minister, c. 1922