What has South Park got to do with it? The "Streisand Effect" was because of Streisand suing a photographer in 2003 causing people to realise where she lived and getting photos of her house, and the phrase was coined in 2005 by Techdirt.
There must be some kind of Mandela effect going on since I feel quite sure I was using this in 1998 after Streisand voiced distaste at the South Park episode.
