[New readers: We read everything at The Coracle, be it liberal, conservative, libertarian, etc., and quote from it from time to time. It's best to be aware of various perspectives as, to paraphrase John Donne, we are "involved in mankind". We try not to be ideologically synoptic.]
In contrast to the many religions, systems of moral thought, and other ancient traditions that have distinguished every effort to better the human condition, postmodernism presumes that all of these endeavors are the cause of human failure. It therefore operates according to just one moral imperative: discredit anything that other people presume to stand for goodness, because the belief that anything is superior to anything else inevitably results in prejudice, interpersonal strife, and inequality.
Thus, the Venus de Milo has no more aesthetic value than a crucifix in a jar full of urine; Beethoven’s symphonies are no more profound than the latest round of top 40 hits; all religions are fundamentally the same, and their “moderate” postmodern adherents are all comfortably represented on the “Coexist” bumper sticker. In a sense, it isn’t culture at all, but rather an anti-culture that measures success insofar as it deconstructs anything that other people value.