KATY, Texas — From a secluded spot in her high school library, a 17-year-old girl spoke softly into her cellphone, worried that someone might overhear her say the things she’d hidden from her parents for years. They don’t know she’s queer, the student told a reporter, and given their past comments about homosexuality’s being a sin, she’s long feared they would learn her secret if they saw what she reads in the library. That space, with its endless rows of books about characters from all sorts of backgrounds, has been her “safe haven,” she said — one of the few...