Yeah, alternative metal, as it is used nowadays, does seem to apply solely to radio rock that is just a little 'heavier' than usual. I still like and use the description, but it is often mis-prescribed imo. Faith No More is definitely a band that I feel warrant that tag, and I'd probably throw Deftones and, to some extent, Tool in with that as well.
NP: Explosions in the Sky - The World is Not a Cold Dead Place
Continuing my post-rock binge. As the album title suggests, this ditches the common trope of dark, gloomy soundscapes in favour of something euphoric and blissful.