Fight Club is about the innate homosexuality of men and how they only want to fuck each other. Consumerism is a metaphor for the burden of heterosexuality (hence Norton's character buying the ying yang table is a demonstration of loserdom, not synergy, men and women are not "supposed" to live in harmony because having sex with women is bad for men.) All of the men in the movie want to be free of it and only find purpose and direction in homosexuality. There is no nihilism, denying your sexuality is just that bad for you. This also why Fight Club is so popular with right wing males like Josh, they try to dress it up in ""philosophy"" but the truth is they're responding to the coming out narrative and see their homosexual natures in the movie.