I have personally been noticing that this attitude is somewhat slightly in decline... either that or I have gone so far out of my way to be disassociated with post modernists that I have grown ignorant of their insipid menace.
Again, the extremely crushing and simple point cannot be over-emphasized: simply that for fans of (for instance) Greek art like myself and others - there was an earlier more 'tribal' stage in their development when they borrowed styles from Etruscans and Persians and so forth - which was okay.... then they hit upon some bizarre (you'd almost think alien-inspired like the monkeys in 2001) age of total excellence in art, learning and sciences --- invented practically everything that is amazing in current western culture from methods of democracy to advanced geometry, philosophy, drama, architecture, the screw ...and even some kind of bronze-age computer