The problem with psychopaths is that they lack a conscience. Healthy moral decision making requires a rational component and a visceral emotional component. Despite the claims that we should make decisions rationally rather than emotionally, if you remove the emotional component, which is what creates a person's conscience, you get decisions that would be amoral or immoral to a person with a properly functioning conscience. This is also why emotional distancing is important in convincing normal people to go along with atrocities like genocide.
This isn't something that's a matter of choice for a psychopath any more than autism is a matter of choice. Their brain lacks a conscience to keep them on moral rails and rational thought doesn't provide a replacement. It doesn't seem to predictably be a result of obviously bad parenting or schooling or influences, though head trauma and early experiences may play a role in it. And it can appear in children as young as 9 or even 6.
There is a ton of information out there on psychopaths so why don't we hear more about in the mainstream media? I think the answer can be found in the article in the second link, above:
"There's still a lot of opposition -- some criminologists, sociologists, and psychologists don't like psychopathy at all," Hare says. "I can spend the entire day going through the literature -- it's overwhelming, and unless you're semi-brain-dead you're stunned by it -- but a lot of people come out of there and say, 'So what? Psychopathy is a mythological construct.' They have political and social agendas: 'People are inherently good,' they say. 'Just give them a hug, a puppy dog, and a musical instrument and they're all going to be okay.' "
If Hare sounds a little bitter, it's because a decade ago, Correctional Service of Canada asked him to design a treatment program for psychopaths, but just after he submitted the plan in 1992, there were personnel changes at the top of CSC. The new team had a different agenda, which Hare summarizes as, "We don't believe in the badness of people." His plan sank without a trace.
Scary, isn’t it? When I was working on my master’s degree, the professors repeatedly told us that in order to be an effective therapist I had to hold the belief that everyone is inherently good. They used that exact wording! I will never believe that all humans are inherently good, and I think subscribing to that belief does a great disservice to many of those who do seek counseling.