My DS14 was very sensitive to specific things when he was younger but not to my memory for Disney films. But it possible he never really watched them. He preferred TV shows about animals and science. He would not, and still won't have anything to do with Charlie & The Chocolate Factory. We never forced him, and he even made a deal with his 2nd teacher once about being allowed to leave the room when the teacher read it out loud. This resulted in a massive tantrum once when because of change in schedule, he thought the teacher had forgotten.
Time & maturity will help. There really is no need to watch Disney movies but if you really feel she will understand her peers better you could try her borrowing some Disney books that describe the plot. While I abhor these books because they are usually very badly written, I could see them being useful in this instance. It's easier not to get so emotional when reading it than watching it on T.V. Once you know the princess is going to have a happily ever after it might be easier to watch the tension. Even if she doesn't watch the movies, reading the books might help her communicate with the peers that are wild about them.
I suspect that the reason for this being common in GT kids is that of most of these movies just go over most preschool kids heads.
