Fairly often in discussions of sf, especially in discussions of epic fantasy, fans use the idea of historical accuracy to either criticize an authorial choice (“That author made their fictional political or military or scientific leader female! But historically, no woman was ever a leader! This book is inaccurate!”) or to deflect other fans' criticism about white male homogeneity of characters (”Well, of course all the characters in this book are white men! Historically, those are the only people who existed! Why are you PC police always trying to make the author include something historically inaccurate, like women?”).
Back in January, Foz Meadows wrote a good discussion of some reasons that the historical-accuracy argument isn't a good one:“ PSA: Your Default Narrative Settings Are Not Apolitical.”
In particular, she provides links to info about lots of historically important women and people of color, many of whom I hadn't heard of, from Tapputi (who Wikipedia says is considered to be the world's first chemist) to Sir Palamedes the Saracen (from the King Arthur legends) to warrior queen Amina (mentioned on a page Foz linked to) to prominent women of the American Old West to Empress Dowager Cixi, and so on.
Here are a couple of other bits of Foz's entry that I liked:
Isn't the assertion that straight white men are narratively neutral itself a political statement, one which seeks to marginalise as exceptional or abnormal the experiences of every other possible type of person on the planet despite the fact that straight white men are themselves a global minority?
[...] such complaints of racial and sexual inaccuracy have nothing whatsoever to do with history and everything to do with a foggy, bastardised and ultimately inaccurate species of faux-knowledge gleaned primarily—if not exclusively—from homogeneous SFF, RPG settings, TV shows and Hollywood.
(I wrote this entry in January; not sure why I never posted it.)