"A mass grave of female remains from 21st Century America was found, save for a single male. Historians believe this is likely the result of the female purges of the Groyper Incel uprising of 2031. The remains of the male are thought to be a "transexual", as many in the American Empire at the time believed a person could choose to become a gender different from their biology by presenting that way socially."
Look I set the stage, I'll let the geniuses from the future figure it out. All the clues are there. If they can't put the puzzle pieces together that's on them.