I have written about this before, so I know I am repeating myself, but just as an illustration to the pictures below...
Oftentimes, I hear "they are just doing their job" about the actions of police officers (or TSA officials in the airports). In what way is that an excuse? A hired killer is also "just doing his job". If the policeman's job is to follow his superiors' orders to rob and murder people blindly, without a thought, then he is not a human being; he is just a mindless beast, and defending against his actions using whatever force necessary is completely legitimate.
The whole astonishing innovation of Nuremberg Trials was that people following their democratically elected government's orders can be criminals, and "I was just following orders" does not absolve one of responsibility.
People in both these picture were "just doing their job". Notice both the main figures and their colleagues, who are looking on. All are criminals.
Police officers who did not rescue a drowning man in this video were also just doing the job and just following instructions:
And looking at the following picture, I am reminded of an opinion of one of acharoinim that "the worst government is better than anarchy". I guess he lived before the 20th century. Even the worst "private" thugs and criminals don't commit the atrocities that government thugs are capable of: