The Chorus.
SBS is a metal album from start to finish. The fact that many metal albums feature non distorted or even non metal sections doesn't mean those albums are "less" metal, it's a matter of songwriting. Ulver's Bergtatt has, like 1/3 of playtime which is not metal, yet it's a full blown black metal album.
SOAD songwriting is not metal oriented, despite featuring distorted guitars, some fast passages, some chugs here and there, even double bass or thrashy drum beats. Grindcore in its pure state is not metal, yet is abrassive and heavy as fuck.