On page 21 of my Guide to Being a Tr00 Metalhead, it confirms: Becoming a death metal fan is not just about enjoying death metal, infact that's just a small aspect of it. It's also about considering all reasonably popular non-death bands to be shitty. This is not an option, but a requirement. There are exceptions to this rule: Judas Priest, Iron Maiden, Metallica, Motorhead, Alice in Chains, Faith No More, Black Sabbath or Dream Theater. You can still be tr00 and listen to these bands.