I thought it was because of the AWDA, there's no wheelchair access to the castle.
And you're all forgetting about the Illuminatti temple where Walt's head resides. He was a 33rd degree Mason and the temple was constructed in a symbolic act between the two world-controlling secret societies. Every year, representives of each come together to perform dark rituals sworn on Walt's preserved skull. Seriously, I read it on this guy's website. A lot of the imagineer's technology was given to them by the Grey aliens who crashed in Nevada in 1947. Area 51 is actually a secret Disney theme park testing ground.