The rock star performed 'Real Wild Child' on the April 7 results show, which saw Pia Toscano depart the competition.
Speaking to The AP, he said: "I was informed very quickly by people who love me and care about me that, if I went on the show, everybody who liked the show was going to hate me and everybody who liked me was going to hate me for doing that show."
He added: "I'm kind of a stubborn person, so that just made me really determined: 'I'm going to... do it anyway'."
Iggy Pop's appearance on the Fox competition, which saw him singing directly to Jennifer Lopez at the judges' table at one point, coincided with the show's Rock and Roll Hall of Fame-themed episode.
He will perform a concert celebrating the life of Ron Asheton at the Michigan Theater in Ann Arbor tonight.
American Idol continues on Fox tomorrow night with a 21st century songs theme, while Katy Perry and season seven American Idol winner David Cook will both perform on the Thursday night results show.