"They" is a short story written by American science fiction author Robert A. Heinlein. It was first published in the April 1941 issue of "Unknown", and can be found in Heinlein's short story collection "The Unpleasant Profession of Jonathan Hoag". It also appears in a number of multi-author anthologies.
Robert A. Heinlein wrote stories set in the future.
Science fiction means that the stories are set in the future. I suspect the system doesn't know this definition.