It's not like this is a new thing with the vocals.. it goes all the way back to the early/mid-80's with bands like Venom, Celtic Frost and Possessed. These are the bands you have to thank for giving rise to the cookie monster death metal vocals. That's over 20 years. It's not like it's a new trend or anything.

As far as I'm concerned, extreme metal bands have always had those kinds of singers.

-jar