It was during the middle of Civil War that I finally bailed on Marvel (after gritting my teeth and hanging on for several years). I never heard about Black Bolt's harem.
Civil War was when I was starting to be able to get into regular comic reading (its still my favorite Marvel event).
Black Bolt's harem was created when a bunch of "Inhumans" from other species just kind of appeared. Black Bolt had just came back to life (in a confusing and not really explained way) and he took one of each species as an extra wife. It was basically a giant FU to Medusa and made little sense (although BB having a bipedal horse wife was kind of funny). He had no reason to take extra wives, he didn't get some kind of big advantage or something. But, it looks like they're just pretending that the Black bolt harem don't exist, and I'm really glad for that.