WILLARD: It's a way we had over here for living with ourselves. We cut 'em in half with a machine gun and gave 'em a Band-Aid. It was a lie. And the more I saw them, the more I hated lies.
Willard sees the hypocrisy that the same commanders who are dropping napalm on villages and burning civilians to death are also performing humanitarian gestures that don't make a huge difference.
COLONEL LUCAS: Did you not assassinate a government tax collector in Quang Tri province, June 19th, 1968? Captain?
WILLARD: Sir, I am unaware of any such activity or operation...nor would I be disposed to discuss such an operation if it did in fact exist, sir.
This is Willard's way of answering "Yes" to this question. Because of the nature of his work, he has to maintain the pretense of acting with intense secrecy even around superior officers who clearly know about his earlier missions.
WILLARD: Oh man...the bulls*** piled up so fast in Vietnam, you needed wings to stay above it.
Willard is talking about how the generals wanted to discharge Kurtz for launching a successful operation without permission. But when the press found out, the generals promoted Kurtz instead. The generals seem to be more concerned with how they're perceived than with pursuing a strategy to win the war.
WILLARD (quoting Kurtz): As for the charges against me, I am unconcerned. I am beyond their timid lying morality, and so I am beyond caring.
Kurtz thinks the higher-ups do things that are effectively as immoral as anything Kurtz does, but view Kurtz as being worse since he's broken the chain of command. They're all hypocrites in Kurtz's not-so-humble opinion.
CHIEF: You're on your own, captain. You wanna go on? Like this bridge: we build it every night. Charlie blows it right back up again. Just so the generals can say the road's open. Think about it. Who cares?
News of the Vietnam war was on the TV news every single day. Were Americans hearing the truth about the progress of the war?
WILLARD: My mission is to make it up into Cambodia. There's a Green Beret Colonel up there who's gone insane. I'm supposed to kill him.
CHEF: What? Oh, that's typical! S***! F***in' Vietnam mission! I'm short, and we gotta go up there so you can kill one of our own guys? That's f***in' great! That's just f***in' great! S***! That's f***in' crazy! I thought you were going in there to blow up a bridge, or some f***ing railroad tracks or something!
Chef thinks it's a "typical" Vietnam mission because it's totally screwed up: instead of destroying the enemy, Willard's supposed to kill one of their own guys. It just demonstrates that the war is an ethical mess.
KURTZ: What do you call it when the assassins accuse the assassin? A lie. A lie and we have to be merciful.
Kurtz believes that the generals are as violent and brutal as he is. He's just open and honest about it.
KURTZ: I worry that my son might not understand what I've tried to be. And if I were to be killed, Willard, I would want someone to go to my home and tell my son everything. Everything I did, everything you saw, because there's nothing that I detest more than the stench of lies. And if you understand me, Willard, you will do this for me.
In Conrad's Heart of Darkness, the Willard character, Marlow, goes to see Kurtz's fiancée after Kurtz dies. Instead of telling her the truth—that Kurtz's last words were "the horror…the horror…"—he tells her that Kurtz spoke her name as he expired. Do you think Willard can spin this one?