And with the magic of compartmentalization, both kinds of people can work together to create a horrible organization that does all kinds of evil around the world.
Actually, compartmentalization allows the two to work together and only enact what they both agree to. The results are not always terrible, they're a mix.
Nah, you'll do whatever you are ordered to or lose your job. You don't need to know why. Scratch that, here's why: freedom. Now you can feel good about that wire you just cut, that letter you just signed, or that "terrorist" you tortured for years.