No, you just have it wrong. Hoopa has been released in Japan and Singapore. We've known about it for much longer than that though, due to some hackers finding Diancie, Hoopa and Volcanion in X and Y's code, long before any of them were officially revealed. Everyone knows about Hoopa and Diancie because both have been officially revealed and have been released in the games. Hoopa is more "popular" because it has been officially revealed, unlike Volcanion.
Because special event Pokemon can't be traded, the only people with access to Hoopa got them from Japanese or Singaporean events. Anywhere else, they receive Hoopa through PokEdit or other exploits.
