The universality of morality is captured in the play's title. The men who are fighting in the war are all Joe Keller's sons, as they are the sons of everyone in America. And yet, by knowingly supplying cracked cylinder heads to the military, he's put all those young men's lives at risk, including the life of his own son Larry. Although Larry doesn't die as the direct result of his father's greed and corruption, Joe is responsible for his death all the same. When Larry found out about what his father did, he was so overcome with shame that he deliberately crashed his plane.

In his headlong pursuit of the American Dream, Joe hasn't just cut himself off from the wider community, or even humanity as a whole, but even from his nearest and dearest. He most probably thought that everything he did was for his family. After all, that's what the American Dream is commonly taken to be about: improving the lot of yourself and your family.

In actual fact, of course, that's not how things have turned out. In effectively turning his back on the community and humanity, Joe has also turned his back on his family. Everyone's life has been damaged in some way by Joe's fateful actions, and in due course, his own life is ended by them too.