It is true that in the Nuremberg trials nazis claimed they were just following orders, were coerced and therefore "not guilty" - Obviously no sane person thinks the subordinate is not to blame, but the leader holds a big share of guilt in any criminal organization.
Whoever fights monsters should see to it that in the process he does not become a monster. And if you gaze long enough into an abyss, the abyss will gaze back into you