A sensational Instagram post claimed Thursday that 14 black girls had gone missing in Washington, D.C., over a 24-hour period. And the hashtag #missingdcgirls went viral. Numerous celebrities, including Olivia Wilde, Bernice King, Taraji P. Henson, Sean Diddy Combs and LL Cool J latched on to the story, assuming that it wasn’t getting attention because America…