Generic meaning that a lot of it sounds very derivative compared to both other bands in its part of the genre and older black metal from the 1990's, particularly Burzum, Bethlehem, Strid and the like. It's not a very original or inspired kind of music for the most part, as much of it is just a direct imitation of music that came before it without offering anything that stands out from tons of other black metal bands, since depressive black metal is a big thing right now. The basement 4-track recording thing has also been beaten to death, and a lot of bands think it's a totally necessary part of recording. There are exceptions, but for the most part, it's definitely not a new or varied kind of music and I'd generally rather just listen to bands that do fresher and more different things if I'm going to listen to newer black metal.
So basically, generic in terms of them perfectly summarizing the definition of the word. I guess it's not automatically a bad thing if you absolutely adore this kind of music and think it's the best thing ever, but it's not one that I'd prefer.