Psychopathy is physical, what you're talking about are SOCIOPATHS.
Both are defined by a lack of empathy, and indeed American society has spent the past 40-50 years promoting a narcissistic "me, me, me, f*** everyone else" as a social virtue...
The defining difference between the psychopath and the sociopath is nature vs. nurture. (respectively).
I do not think most Americans have significant malfunction of the prefrontal cortex required to be classified as psychopaths. Certainly many of our leaders and your religious extremists likely do. See the recent studies that show violent religious extremists have severe dysfunction of their ventromedial PFC.
Just as the less function of the prefrontal cortex is directly proportional to gullibility and religious belief. Those with overfunction (like me) struggle with extreme skepticism and are oft outcast because things like "religion" and "belief" are chemically incompatible with how our brain works. (I learned a lot about this because of my own condition)
But no, this isn't physical. We have a society that fosters the same lack of empathy found in the psychopath; and the clinical definition for that is sociopathy. It is a conditioned response, not physiological. Psychopathy is completely the wrong word.