There's an entire genre of articles on the theme "why is it so hard to find historic evidence for female same-sex relations?" It covers everything from the types of erasures and displacements that Faderman talks about in this article, to the deliberate and selective exclusion of f/f vocabulary from the Oxford English DIctionary (which continues the process of erasure to this day, as people relying on it to be complete and detailed). Time after time you get slapped in the face with the understanding that f/f relations were erased because people considered them shameful and embarrassing.