The Red-haired kid was a kid from Homer's childhood, who founded the "No Homers Society" in his treehouse.
History[]
When Homer wanted to enter the treehouse club, the kid said that they were no Homers allowed, and then Homer points out that they let in Homer Glumplich. It was then explained that there couldn't be more than one Homer in the club because it was a No-Homers Club.
Joey, Billy and Homer Glumplich were three of the kids in the No Homers society.