CiG
The Veils of Negative Existence
I'm not saying that calling black metal alternative metal is an established usage of the latter. I'm saying that by the definition of alt metal, a lot of black metal should count if there's to be any consistency. My argument stands; music indistinguishable from black metal in terms of riffing, pre-dating established "black metal", exists, and it came about by and large in the alternate scene.
If there's to be any consistency, Black Metal shouldn't even be a genre, because the bands that fall under the category often sound very different on a technical level.