The Wall is not about Art.

Artists in Berlin, disgusted that the graffiti on the Berlin Wall right after the fall of the GDR was being celebrated for its own sake in a bourgeois, quasi-spiritual manner, scrawled this and a long yellow line across on the Wall. (According to Bridget Fowler in Pierre Bourdieu and Cultural Theory, p. 178)

Trve Metal and Bourdieu

While Pierre Bourdieu is talking about bourgeois (art/serious) music, this argument the French sociologist makes in an interview with Cyril Huvé could be applied to discussions (and fights) in current pop music genres and subcultures, like metal, hardcore, punk, hip hop, techno, indie, folk, etc.: 

“What is intolerable for thise who have a certain taste, that’s to say, a certain acquired disposition to "differentiate and appreciate” as Kant puts it, is above all the mixing of genres, the confusion of domains. Radio or television producers* who juxtapose a classical violinist and a fiddler, (or, worse, a tzigane violinist,) an interview with Janos Strarker and a chat with an Argentinian tango director, and so on, are – sometimes knowingly, sometimes unconsiously – performing ritual barbarisms, sacrilegious transgressions, by mixing what ought to be separated, the sacred and the profane, and combining that which the embodied classifications, tastes, require to be separated.“ (Pierre Bourdieu. Sociology in Question. SAGE, 1993. p. 104)

*Or music bloggers, teenagers with a youtube channel, …