>How was it a bourgeois influence when the vast majority of rock and metal fans weren't bourgeois,

The fans may not have been porkies, but the musicians were. Rock music is fascist. It was a CIA PSYOP.

>a lot rock music had major anti-imperialist or anti-capitalist themes(John Lennon

Liberal hippie bullshit, lots of anti-communism mixed in ("You say you need a revolution…").

The USSR did fail to promote new proletarian music to an extent, but shitty boomer noises were not the answer.

>What makes this hypocritical is that at the same time ballet and classical music was kept in high regard, when these arts are to this day just entertainment for decadent and pretentious nobles and the grande bourgeosie

This kind of music is socially organized (in orchestras, practice sessions, etc) and performed by everyone. In comparison, the kind of music that is distinctly stamped with the approval of the bourgeoisie is rock music that focuses on stardom and expropriates musical performance from the masses. Orchestral music was accessible to all in socialism. Would you complain also that the socialists preserved beautiful tzarist architecture and made it accessible to all instead of demolishing it and replacing it with bourgeois skyscrapers?