Captain Miller: "I don't gripe to you, Reiben. I'm a captain. There's a chain of command. Gripes go up, not down. Always up. You gripe to me, I gripe to my superior officer, so on, so on, and so on. I don't gripe to you. I don't gripe in front of you. You should know that as a Ranger."
Private Reiben: "I'm sorry, sir, but uh... let's say you weren't a captain, or maybe I was a major. What would you say then?"
Captain Miller: Well, in that case... I'd say, "This is an excellent mission, sir, with an extremely valuable objective, sir, worthy of my best efforts, sir. Moreover... I feel heartfelt sorrow for the mother of Private James Ryan and am willing to lay down my life and the lives of my men - especially you, Reiben - to ease her suffering."
https://www.youtube.com/watch?v=DhbObZEF0Mc Saving Private Ryan
I don’t get it. He said gripe to his superior but he is basically kissing ass?
No, that is exactly how you inform a superior officer that you believe the mission is a waste of time, effort, equipment, and manpower, and will probably get everyone killed for next-to-no benefit.
I interpreted it to mean that he was still Captain and part of his job was to keep up morale and model positive attitude. Even hypothetically, he was not going to gripe to his troops, and as far as they are concerned, he believes it is a worthy mission. He was jokingly modeling the proper, positive attitude. All this was understood by his men.
I’d add that the answer was clearly over the top, thus sarcastic, thus he is agreement with his soldiers.
No, I did not interpret it that way. Perhaps he did think the mission was dumb, but he was not letting on even subtly.
It's best understood in the context of the story. I highly recommend the movie.
He's being sarcastic about his approval of the mission they're on, but is making the point of not overtly complaining to his unit.