The phrase "The Beautiful People" came into vogue in the '60s, entering the popular lexicon in 1967. That year, a book by Marilyn Bender called The Beautiful People: a Candid Examination of a Cultural Phenomenon - the Marriage of Fashion and Society in the '60s
was published, which is where Manson got the title to this song.
The phrase quickly became used as a demeaning identifier, as any grounded individual would certainly object to being classified a "beautiful person." The Beatles used it incisively in their song "Baby You're A Rich Man
," and many journalists picked up the phrase. We found this from a 1967 NME
article on Dave Davies of The Kinks, where the author responds to a comment from Davies that he likes to stare at the moon and let his mind wander: "Before anyone reads into that remark that Dave has joined the beautiful people perhaps I should mention that his version of a 'beautiful person' is someone who plays football."