The USA is a melting pot of cultures, so we would often rather steal ideas from other places and bastardize it to make it our own rather than come up with something truly American from scratch. We have our American "pilsners" that are nothing like Bohemian pilsners except that they are light in color. Then we take India Pale Ale, which once upon a time was one of the most bitter beer styles known, and take it to the Nth level of bitterness but still continue to call it IPA, when it doesn't resemble the original at all. Then we go even further and invent something stupid like Black IPA, which is neither from India nor Pale. We should call that one something else... like, say, American stout?!? American stout has been around for probably 30 years but it didn't get popular until we threw it into the IPA category, because Americans sure love their IPAs. But stout... nah... stout's got too much flavor. No, we'd rather add black food coloring to a regular IPA so it doesn't taste acrid. Black food coloring!? It's all such a joke. It might not be so popular if we called it what it really is: American Very Hoppy Ale with Black Food Coloring. Now that's a great style descriptor. A little too honest. No... we'd rather call it Black India Pale Ale. Simultaneously oxymoronic, and moronic.
We Americans are just plain goofy. At least we know what flavors we like if we can't be creative enough to come up with names for things. Hops hops and more hops.