Who says they lost it? That would imply they were born with it. The role of nature vs nurture in sociopathy is debatable.
The closest thing to a real "Batman" style villain in the real world is the psychopathic personality; a narcissistic and antisocial personality
www.mentalhelp.net
From your link:
"It would be better if psychopathy was completely caused by nurture, because then we could more easily do something about it, conceivably. To the extent that genetic factors are at work then even if the problem of violent abuse is solved in some unlikely future utopia, there will still be mechanisms at work creating psychopaths among us. Not really an uplifting thought."
Sadly, I am all too aware of the cautionary advise that you offer here, and sufficiently so that I intentionally avoided the validity of the point you make here. I did so to avoid the difficult problem I have, in counter distinction to empiricists as to what it means to know anything.
In short, I believe that the modern science of psychology has as its origin the study of the laws of behavior that apply to people as they are, not as they may become. For me, this means that psychology is the science of the reactions of people who are actually asleep, robots obeying motivations they are completely unconscious and unaware are actually running their lives. In the East, according to a completely different kind of science, knowledge derived from self awareness, these unconscious force is sometimes referred to as the Commanding Self and to which I generally just call ego.
This then implies, at least for me, there are two kinds of knowledge, one based on knowing how sleeping man operates and one based on the psychology of the awake, what I would prefer to think of as the real knowing.
This, of course, puts me into all kinds of difficulty when talking with those who don't share a similar experience.
The byproduct of though is that for me the knowledge obtained and accepted as universal via ordinary psychology is collected and offered by people who themselves are asleep, a fact which renders their judgments unreliable in my opinion.
It leads to comments like the one I quoted above, "problem of violent abuse is solved in some unlikely future utopia".
No before yes, please. For me the unconscious motivation behind the statement above is that it will be never when I look at myself and find the problem of violence is that I will not ever allow the consciousness to arise in me that I am the source and cause of such violence. We are violent because we are asleep and we would rather die than awaken.
Of course the problem is utopian in a far of future for that reason but the actual experience of awakening for any one of us takes only a second. It is our unconscious acceptance and adjustment to a life of sleep that keeps form allowing us to hear anything from the world of the awake. We are deeply afraid to feel what we would feel if we allowed ourselves to feel what we actually do feel, almost infinite self hate.
So for me also, the recognition that there may actually be people who can't feel empathy genetically is the first thing we as sleepers will run to for cover as to why any hope for humanity, ourselves awakening, is pointless, hopeless, and a pipe dream.
We are all just as insane as any Trump conservative when it comes to denying reality.
So I am willing to admit that there may be folk who are actually not truly human among us, serial killers as a possible example, I would want to be careful that I don't go down the road that says humans are not different than ants.
I believe that what we call God is a reflection of what the conditions that exist in our universe made possible for us, that we are a mirror of a mirror in infinite regression such that the question of God or man's projection become completely meaningless.
Oh my Beloved, wherever I look it appears to be Thou. The Lover and the Beloved are one and the same thing.