Little girls want to see the princesses, they love watching their films and television shows. Is this bad? Might as well trash every single television show/movie out there, such as Star Trek, and other franchises.
I'm an adult male, but I loved the Princess and the Frog (which won an Academy Award for best animated feature), and while I won't wait in line for Tiana, I like seeing her walk around the park and interacting with folks.
Take a close look because this is what quality looks like:
No, little girls and adults aren't "bad people" for deriving enjoyment from seeing their favorite characters in the park, if they took away the princesses people would go nuts.