Disney does not sponsor, welcome with signs, or have anything to do with Gay Days at Disney. This is a private organization that decides to meet up at the mega resort every year.
Disney does let them privately book. That said, they’d be tickled to let any fundie or Catholic, etc. group privately book too. The only color of the rainbow they really care about is green.
Disney allows the Gay Day organizers to use the jealously guarded trademarks of the Mickey Mouse profile and Mickey Mouse ‘Mouse Ears’ without legal challenge year-after-year.
Given that if I produced an image with those trademarks I’d be almost instantly sued and ordered to cease and desist I can only and reasonably conclude the the Disney Corporations’ deafening silence in this matter is an active endorsement.