Are postmodern writers choking on a kind of shoulder shrugging "irony" that excuses them from the toil of creating a committed art while operating under the claim that they are refusing to impose a white man's meaning on the world?No more, it would seem , than any other writer scribing under the modernist tenet of "making it new", or to another extreme, 'defamiliarizing" (from Bahktin) recognizable settings , characters and schemes in a language that's meant to provoke readers to see their world in new ways. This is a modernist habit that the new, cubist, cut-up, stream-of-conscious takes on the world will sweep away past aesthetic interpretative models and lead one to a the correct formation of the world-- there remains a faith that language and other senses can apprehend and describe a tangible , material world and capture its complex composition, a "metaphysics of presence" that art can unearth.
Irony, in this sense, is usually contained within the story, a result of several kinds of narrative operations coming to a crucial moment of ironic intensity that then drives the story into directions one , with hope, didn't anticipate. Post modern writers start off with the intent of being post modern from the start, and rather than have their inventions gear us for a challenge to see the world in a truer light (contrasted against previous schools of lovely language but false conclusions), the project is to debunk the idea of narrative style all together.
Irony is intended to demonstrate some flaws in character's assumptions about the world, a description of the world that emerges contrarily after we've been introduced to the zeitgeist of the fictionalized terrain. Post modern writers are ironists of a different sort, decidedly more acidic and cynical about whether narrative in any form can hone our instincts.