I mean - let's be honest - there is a reason why somebody chooses to become a cop. And more often than not - this very reason isn't about "helping people". It's more likely about enjoying the exertion of power over people. There is a stronger psychological similarity between ordinary hooligans and police men than what is good. It's also always the police who will eagerly suppress people in case a state turns increasingly totalitarian - policemen don't like thinking for themselves - which is why they choose those hierarchical jobs in the first place. They like to have action and the feeling of adrenalin.

Also it's worth thinking about this - the SS in Nazi Germany was made up of about 2% of the population. Now this personality type who would do SS jobs didn't just go away - the root is of psychological nature which is most likely more or less uniformly distributed within any population. Now those guys - in that psychological, statistical sense still exist - what do you think what kind of job they will choose? Elder care? Most likely either military or police.