That may be enough to explain it, but I do think groups that compete in committing the worst public atrocities are somewhat unusual—Hitler and Stalin made some effort to conceal the worst of what they were doing.
If you look at pre-20th century (and especially pre-Enlightenment) history, you see that it is Hitler and Stalin that are unusual.
If you look at pre-20th century (and especially pre-Enlightenment) history, you see that it is Hitler and Stalin that are unusual.