Have you ever been in the military? I'm guessing not.
Glib though your answer is it hasn't been that long since people were shot for not following orders. And at 17-18 years old you're unlikely to question much you're told to do, especially after training/indoctrination. Most of the time I had no idea what I was actually doing or why, but when you end up having to fight for your life and those of your muckers you do what you must trying to survive. Trails come if you survive.
https://en.wikipedia.org/wiki/Superior_orders