In “Bridgerton,” the new Shonda Rhimes period drama on Netflix, the lords and ladies of early 19th century Britain are depicted as Black as well as White. Why? Washington Post television critic Hank Stuever explains it this way: “A Black character stops to explain, grandly, how and why this society came to be integrated. (Answer: because the queen is a person of color.) Not only does it not make much sense, but it seems like an unnecessary wrench thrown into a completely sensible and revisionary romp: People of color are here because they should have been here all along. Isn’t...