I'm always leery of these vague articles that make a lot of insinuations. There's one quote from Miley:
Honestly, musicals? I just can't.What if this was real life and I was just walking down the street on Rodeo Drive and all of a sudden I just burst into song about how much I love shoes? [...] It would get hits on YouTube.
which is a valid POV even if you don't agree with it. She never mentions Glee, or that she "hates" it, you have to trust the article that it's what she's saying when more than likely she just hasn't watched it because the genre isn't her cup of tea.