"Humans" have cleverly delivered a modern synthesis of a long tradition of sci-fi narratives that blur the distinction between humans and intelligent human-like machines. Like those narratives that came before it, the series explores what will happen when we develop androids that look and behave like us.
I don't think selfishness comes naturally. I believe it develops over time through socialization and, in all honesty, it doesn't make you a good person just because you donate to a charity (looking at you stuck up rich people). Similarly, it doesn't make you a bad person just because you passed up a volunteer opportunity (more of a note for myself).