The above quote refers to Papa, and it speaks to his identity, or lack thereof. Papa is a hard worker, who'd made a good life for himself in America. He sees himself as a citizen of his adopted country, he made his home is America because he wanted to provide his family with a better life, and because he had an increasing lack of respect for the samurai class of which he was a member. As a result of the war, the reasons for Papa having come to America, as well as the contributions he made as a resident of the country no longer mattered. He was imprisoned, and his family sent to a relocation camp based upon their heritage..... not their actions. In Papa's eyes, he was no longer important.... he'd ceased to exist, and he was unaccepted on all front.