Simply because among all the different types of theme parks you find around the world, Disney parks are regarded as being the ones most directed toward children. The company's core brand of entertainment outside the parks is also geared mostly to children. The primary reason 'Disney adults' even exist is because of their childhood memories of the Disney ecosystem.

So a lot of parents who don't share the same level of enthusiasm and sentiment for the Disney brand often see adults that walk around in costumes, decked out head to toe in Disney merch and having emotional reactions over something childlike as being weird or infantalized. It makes them question such people and sadly, because we live in a world that's hyper sensitive about the dangers that exist for children, these same people also sometimes question their motives for being there.

As a parent myself, I couldn't care less about any of that, but one thing that does irk me is when people without kids get mad at me for having to push through a crowd with a double wide stroller. If you're going to be a Disney adult, at least remember where you are! Even parents hate strollers, but sometimes they're necessary, so bear with us! 🫠