@RickiTarr I think from a psychological lens, the way we talk about what is termed "psychopathy" is based on a lot of junk science and popular misunderstandings of personality disorders.
But even deeper than that, when we speak about psychopathy we're talking about multiple things like social behavior, cognition, personal values, empathy and social norms all kind of muddled up together. So, some operationalizing is needed.
I think it's also difficult to tease out because we live in a world that mass manufactures violence and incredible amounts of harm. We also have a massive multinational disinformation and propaganda infrastructure that has been designed to justify said harm. Mass manipulation and miseducation allows for unfathomable cruelty to be reproduced on a worldwide scale without folks batting an eye, so for me this idea of behavior that lacks empathy being a unique thing is nonsensical.
In terms of purpose, yes, there is a purpose. It allows for an intensely unequal consolidation of power and makes a few people filthy stinking rich.