YANBU
If it's not hurting anyone, people should be free to do the things that make them happy. It's absurd to expect that everyone would enjoy the same things - and there are literally hundreds of threads on here about children differing from their peers in their interests & outlook, why on earth would that magically change in adulthood?
Things can be enjoyed on different levels, too - there are scads of babies busily appreciating a wide variety of classical music; and countless toddlers are ballet-mad & watch DVDs of the mainstays of classical repertoire almost in a trance. Equally, an adult might be analysing Disney princesses from the feminist perspective; looking at the [lack of] representations of POC in Disney films; or use Disney as a break from thinking/a kind of mental comfort food if they have a particularly [mentally] tiring job.
I collect Girl Guide fiction - mostly books from the first half of the C20, but I've also got paperbacks about Brownies from the 1970s/80s. I'm interested in both the history of Girlguiding & the [social & cultural] historical context of the books. Doubtless some people would judge me if they saw me reading kidlit though. I've never understood the frantic judging of other people's choice of reading material. Of the people I know, it's the people who were reading Dickens at 10 (etc blah) who are most likely to read YA fic or indeed anything else they fancy - they're not reading it because they lack the sophistication to appreciate Great Literature, but because they don't feel constrained to read the things other people think they should. Personally I can't get on with "chick-lit" at all, but I wouldn't denounce it, nor would I start making wild claims about the intellectual capacity of the people who choose to read it.
It was one of my ballet friends (she "only" watches, I dance & watch) I went to see the Harry Potter play with last year. Me in a Gryffindor t-shirt, her in a Slytherin one. She's also into opera, whereas I'm much more into choral music. Both of us are into theatre, though she goes more often than I do - she has some serious ticket ninja skills (& the physical ability to sit in places my wonky joints do not permit).
People are complex. In some cases, they will be exploring the concept that "it's never too late to have a happy childhood". Regardless of the state of your childhood it's quite healthy to keep doing "childish" things if they still make you happy & aren't harming anyone - walking on [low, safe, public] walls, climbing trees, going on the swings, kicking leaves, pretending to be a dragon on a frosty morning, skipping rather than walking, rolling down hills, paddling in the sea... happiness is good for you.
There's no obligation for people to like things like opera & ballet & Chaucer & Norse mythology anyway. It would be a very dull world if we were all alike, and intelligence is not measured by an individual's interests.
And on that note I'd better get to bed. Am going to a local guiding thing with some of my older Brownies later on & could do with being awake.