"People trust each other less and less these days, and I see some danger of further fractionalisation here. Instead of watching this film and gleefully pointing out who are the psychopaths from the people we know - we might better ask ourselves 'How high is my own capacity for empathy?'

Rather than looking at being a 'psychopath' as an on/off proposition, it might be wiser instead to measure the positive aspect of empathy, and have a scale ranging from 0 to 100 that reflected it. 

This would cause us to view people on the low end as being 'Empathetically Challenged'. It would corollate with all the film's evidence, while providing a clearer picture that answers that question about why the large masses of us can be coerced into temporary, psychopathic actions by authority figures.

The average person in the dark ages had less predilection towards empathy than we do now, and thus torture was not only allowed but used as entertainment. Few ever thought to ask 'How would it feel if that were me?'

I suspect that while 1% of us fall into the dangerous 'Empathetically Challenged' percentile (and move up the chain of command more easily), only a slightly higher number can consistently be expected to have the greatest capacity for it. Thus only a few people refused to push the electro shock button. 

In between the two extremes lie most of us. 

In the seventies people used to hitch hike, even though the odd story would crop up in the news. It wasn't until the media created the depiction of the 'psychopath' that both hitch hikers and drivers simply felt it too risky. Ask yourself why Hannibal Lector became a cult hero? Perversely, people can equate the sociopath or psychopath with higher cognitive powers.

Finally. another thought difficult to wrestle with: 

Since these elements have most likely always existed in human society, it could be posited that it is their dynamic push and pull that has gotten us to where we are today. Perhaps they both play a role. The Hitler and Napoleons versus the Jesus and Ghandis of history. One organises ruthlessly, the other stops the madness and provokes reflection (on occasion).

I know one thing. if I was a world leader faced with having to sacrifice a certain 5,000 people to save a hypothetical million, I would falter. We almost demand a degree of empathetic detachment from people who make such decisions. 

Certainly, wherever history leads the people of this planet, we will have to acknowledge the role of our 'psychopathic' or 'empathetically challenged' elements (often leaders) in causing the development of that future world.

Bottom line:

Condemn no one. Move forwards, onwards, and upwards to the light!"