As someone who enjoys both "true metal" bands (Classic stuff, Metallica, Pantera, Iron Maiden, and "respected" bands like Dethklok, Dream Theater to name a few), Power/Neoclassical/Whatever Metal (Stratovarius, Rhapsody, Heavenly, Dragonforce, Versailles, Yngwie Malmsteen, Michael Romeo, etc) and "fake metal!!!!1111!!!!ONEONEONEONE!!!" bands (Avenged Sevenfold, Bullet For My Valentine, Trivium, Atreyu, Slipknot, etc) I have to say metal elitism is pure bullshit. Elitists barely have any arguments at all other than saying "X band is emo" "X band fans are angry teens" and a huge variety of ad hominem arguments. And it doesn't exist only in metal. Jazz fans can be pretty elitist as well, saying smooth jazz and acid jazz are not TRUE and HONEST jazz. Same goes with Classical Music fans who say shit about any genre of music that is not Classical, or about atonalist composers. There's even folk music elitists in my country saying how a lot of newly formed folk bands are not folk at all. So yeah, it's not only happening in metal.