A hoppy porter and a black IPA are not the same thing. There should be little to know roast character in a black IPA with medium high to high hop aroma and flavor. Whereas, a porter is defined by dominant malt character and roast character in flavor and a aroma. The bittering can be high, but hop flavor should be medium but not dominate the malt character which is different than an black IPA. Also, a porter should be balanced towards the malt whereas a black IPA by it's very nature as an "IPA" is not.
There no generally-accepted standard for what is and what is not a black IPA at this point in time. I have tasted black IPAs that taste like highly-hopped strong porters as well as black IPAs that taste like colored IPAs.
I beg to differ:
From the BA guidelines, it may not be BJCP, but I expect/suspect that they will be included in some way shape or form when the new guidelines are released very soon:
American-Style Black Ale
American-Style Black Ales are very dark to black. Medium caramel malt and dark roasted malt aromas are
evident. Hop aroma is medium-high to high, with fruity, floral, herbal or other hop aroma from hops of all origins
contributing. Medium caramel malt and dark roasted malt flavors are evident. High astringency and high degree of
burnt roast malt should be absent. Hop flavor is medium-high, with fruity, floral, herbal or other hop flavor from
hops of all origins contributing. Hop bitterness is medium-high to high. Body is medium.
Original Gravity (ºPlato) 1.056 - 1.075 (13.8 - 18.2) ● Apparent Extract/Final Gravity (ºPlato) 1.012 - 1.018
(3.1 - 4.6) ● Alcohol by Weight (Volume) 5.00% - 6.00% (6.30% - 7.60%) ● Bitterness (IBU) (50 - 70) ● Color
SRM (EBC) 35+ (70+)