My experience tells me that some of the cruelest people on Earth can be....

[Irish_Dem]

1. I don't know if they are the cruelest on earth, but yes they can be crazed killers.

I think it is a combination of PTSD and the social psychology findings that humans
when given power and authority over others can readily descend into brutal torture and murder.
This is especially true when they are masked and anonymous.

We see this as well with the US civilian police force.

My mother was a US military registered nurse during the Korean War.
She served stateside at a military MASH receiving hospital.
The wounded men from the Korean combat zone were sent there
for additional treatment and recovery. She was taking care of men
who had fought not only in Korea but WWII as well.

Some of the stories she heard from the men along the same lines you are discussing were
very chilling.