The narrator is interested in the debate between men who doubt being, and men who accept it without reservation.
Those who believe that human existence is good, as is told in Genesis, have a basic faith that the narrator calls a "categorical agreement with being" (6.5.2).
But everyone, he reminds us, feels that defecation is disgusting. Which means that those who maintain this faith in the good of existence deny defecation – they act as though it does not exist. Such an aesthetic ideal is called kitsch.
"Kitsch" is a 19th century German word that has taken on meaning in most Western languages. It is a perspective, which denies everything it finds unacceptable about human existence.