It's believed, through the most recent of research, that sociopathy is rooted within the brain itself.  Information is chaotically scattered throughout both hemispheres, rather than being stored in and transmitted throughout the proper regions.  Some mental faculties never come to fruition at all, largely those associated with emotions.  This gives rise to the term "both without a conscience": the conscience literally fails to develop.  This isn't the person's fault, and to blame them as Stout does shows the same lack of regard a sociopath supposedly has for other human beings.

A sociopath functions in society -- or attempts to -- through mimicking the behavior of those around them.  They don't experience most emotions the way "normal" people do.  This disconnect usually leads to an empty, miserable existence that's far more worthy of sympathy than scorn.