"It has NOTHING to do with Vietnam"
Actually, you are wrong in this regard. Modern day (at the time the movie was being developed) was reflected in the movie in that our military was fighting with one hand behind our backs, and one hand tied in DC. Col. Kurtz reflected what behavior was required to succeed in Vietnam but the US was too weak, or weary, to accomplish it. "If I had ten divisions of those men, our troubles here would be over very quickly. You have to have men who are moral...and at the same time who are able to utilize their primordial instincts to kill without feeling."
But instead in Vietnam, we had the exchange between Willard and the soldier in the trench: "Hey soldier, do you know whose in command here?" Soldier: "Aint you?"
Great lines throughout. My navy buddies and eye used to watch the movie over a few beers, and recite the lines.
Say, Tulsa, you must have been with that Navy unit over in Picksley... Didn't they get busted for eating corn without removing the husks?