Why we need psychopaths (part 1)

A reader studying psychology/criminology wrote a research paper about why we need psychopaths and wants our thoughts/feedback before she finalizes it:

Antisocial Personality Disorder is one of the most frightening, controversial and misunderstood terms in the realm of social sciences. This paper intends to dispel myths, explain alternative perspectives, offer insight into a characteristic impersonal section of society, and promote the sustenance of humanity using a combination of psychological and sociological theories to encourage a purposeful alliance between disparate groups: the empathic and those without a conscience.
***
Psychopaths are a subset of the population that, due to drastically different personality constructs, have the ability to perform unique societal functions.
***
Where a person falls on the spectrum of ASPD depends on a variety of factors. The Freudian framework describes this structure of psyche as being determined within the first five years of life. While Freud's reasoning of why this impairment occurs is questionable, his stance that it is broadly due to early childhood trauma rings true with most mental health professionals (Bowlby 1951). Regarding Freud’s research it is said that the defense mechanisms used to protect a psychopath are usually the cause of their downfall. Immature defenses include denial, acting out, projection, displacement and repression, which all tend to have immediate rewards but long term negative consequences. This would further illustrate a spectrum of behavior segmented within the context of ASPD. More mature and high functioning sociopaths would use corresponding mature defense mechanisms that would be more socially acceptable and consistent with maintaining a normally functioning personality. That also means that the traits of ASPD that require delayed gratification would also be more pronounced, such as excellent self-control, higher intelligence, manipulative and calculating behavior, as well as the ability to maintain a normal outwardly appearance.

It appears as though ASPD runs on this spectrum with highly intelligent, patient manipulators on one end and impulsive, violent criminals on the other. Because the tendency toward crime worsens with more severe forms of psychopathy, this spectrum serves as a “self-cleaning” mechanism for society. The dangerous psychopaths more often than not end up in prison fairly soon upon reaching adulthood which reduces the risk for substantial danger to others. As more of these criminally inclined are incarcerated, what remains is the other half of the spectrum. While it will always be difficult to obtain accurate statistics on mental health diagnosis because many are undiagnosed, untreated, or have several overlapping conditions, enough information has been gathered to provide an estimate. Harvard psychologist Martha Stout reveals that 4 percent of ordinary people—one in twenty-five— do not possess a conscience. Since approximately 75% of the prison population meets the criteria for ASPD (Hare 1999), most of the remaining psychopaths operating in society are high-functioning, highly intelligent and appears to be ordinary people.