I Exist

What the sense of obligation the universe is referring to is that it does not owe mankind anything. The world will not bend to mankind, and mankind is on its own. It made man, but it does not care about man. That is what the quote means. The civil war means that they're on their own. Man's existence is insignificant. The United States had felt as if the universe was on their side, until turmoil struck and that they're trench deep in a warfare against their own brethren. That is what caused the statement of, "Sir, I exist!" because the man is trying to get the universe to acknowledge him.
We are our own trailblazers of fate. We control our own destiny, not the universe. The universe does not owe you anything. To follow an idea of Mao Ze Dong, he says that we are not obligated in responsibility towards the next generation or anyone for that reason, and the universe would defend it. It does not owe anyone anything. We are our own method of survival, our own tools, and our own resources. The universe was generous enough to give us life, and now we must (on our own) preserve it.