Put it this way. Assume metal is a party is actually meaningless because pretty much anything could be a party. Oh, except perhaps work/school which may explain why we have if it's not work/school = it's party time people.
Therefore nothing sets metal in particular apart from say a poo flinging contest, a bout of balloon popping and cake gobbling, etc. It's actually worse, because metal noises is just some stuff playing while The Party happens. Metal therefore is a peripheral accessory to a party. Clearly then, The Party, not metal, is what's meaningful, or at least the actual goal. If metal plays in another setting, it serves as residual nostalgia from the most recent party.
It's Pavlovian in a big way. Replace metal noises during party time with poo gobbling contests and the animal is then trained to adore poo gobbling because the activity is now better associated with The Party. Any time a poo gobbling contest occurs, the party animal salivates, where before it would salivate any time metal noises play.
Simply, if you're not a moronic slug, you're Elitist, which we are expected to take to mean "not just another moronic slug", and afterward take offense at this revelation.