IMO, there is a big difference in screaming and growling. That low gutteral growling vocal, and yes they are speaking in growls, that I cant understand is what I dont care much for. A tastefully done growl as an accent to the music is acceptable. Bullet for my Valentine uses tasteful growling, IMO.
Screams can be overdone, too. I dont like to listen to an entire song where the vocalist is screaming at me! Which is probably why I never liked Little Richard that much, he takes screams to the exreme. That to me is not what a vocal talent is all about. But screams can be fantastic in songs, like the song "Psycho" by the Sonics. And another good screamer is Roger Daltry in "Wont Get Fooled Again".
Screams can be overdone, too. I dont like to listen to an entire song where the vocalist is screaming at me! Which is probably why I never liked Little Richard that much, he takes screams to the exreme. That to me is not what a vocal talent is all about. But screams can be fantastic in songs, like the song "Psycho" by the Sonics. And another good screamer is Roger Daltry in "Wont Get Fooled Again".