I thought it was to lull the reader into a spiral of boredom just before throwing you back into a super-mega-ultra-violent scene. It takes place in the MTV era as well as music magazines being pretty popular. Having an “intellectual” conversation about music in order to have one toe in mainstream pop culture seemed to fit the character for me. Bateman had obsessive compulsive behaviors which included hygiene, working out, music, and killing. The first three are pretty mundane, but the last one is so inhumane and absolutely intolerably extreme. It’s one book I’ve not wanted to read a second time. I haven’t seen the movie (except for a few scenes that end up on social media a lot) because I couldn’t see how a movie could possibly be made to be anything like the book yet still be watchable.