The left hates standards -- moral standards, artistic standards, cultural standards. The West is built on all three, and it has excelled in all three.That's over-reach, conflating scholarly inquiry into what makes up moral, artistic, or cultural phenomena worthy of study with political evaluation of standards that confer evolutionary advantage on their adopters. It is the cultural left's deconstruction of those standards that is rendering young people unemployable.
Why does the left hate standards? It hates standards because when there are standards, there is judgment. And leftists don't want to be judged.
Thus, Michelangelo is no better than any contemporary artist, and Rembrandt is no greater than any non-Western artist. So, too, street graffiti -- which is essentially the defacing of public and private property, and thus serves to undermine civilization -- is "art."
Melody-free, harmony-free, atonal sounds are just as good as Beethoven's music. And Western classical music is no better than the music of any non-Western civilization. Guatemalan poets are every bit as worthy of study as Shakespeare.
There's a Live as Free People essay, "The Sneering Age," that's all about radical skepticism. "We lose a solid foundation. We lose our essence as humans. We lose the real world out there, existing objectively and in its own right, apart from and independent of our perceptions and understanding."
That only becomes a problem when people read too much into playing with ideas. There's a Stanley Fish bon mot, "Postmodernism is liberalism taken seriously," where "liberalism" refers to No Final Say. And Mr Fish precedes that phrase, from his Save the World on Your Own Time, with "You have to go with the evidence you have, even if it is true that the evidence you have may be overtaken in the long run."
Put another way, there's enough evidence that adoption of bourgeois conventions and listening to Beethoven confers evolutionary advantages that people raised in the streets or the rain forests might gain by adopting.