A normal distribution of empathy across the human population leads to about 2.3% psychopaths.
Another 13.6% or so will have psychopathic tendencies. That is one of six people actively “evil.”
Another 53.2% of the distribution will have more or less average empathy so that two thirds of the population are evil, aligned with evil or content to go along with an evil program.
Only one person in three really gives a shit about the other two.
Nazi Germany should be more understandable, now.