The reviews for Disney-owned FX’s new hit miniseries “Shōgun” have been absolutely glowing. That is, apart from one notable exception. The series, based on a 1975 novel by James Clavell, follows the story of an English explorer in the 1500s who finds himself smack-dab in the middle of an intense political conflict unfolding in the Japanese empire. Though many seem to be enjoying the show, one critic — writer William Spivey — felt it was failing for one major reason: There is no black representation. The article, which originated as a blog on Medium, has received some seriously harsh criticism,...