Postmodernism is a
philosophy that holds that there are no such things as
truth, facts, or objective
reality, and such concepts are oppressive tools of the white male
power structure. A common postmodernist refrain is "Perception is
reality". Rather than there being an objective
reality that everyone is perceiving through lenses that can and do contain distortions, postmodernism teaches that reality is different for every person, and there is no such thing as a false narrative. An old expression says that "There are three sides to every story: yours, mine, and the
cold, hard
truth". Postmodernism gets rid of that third side. Everybody's worldview, right down to the mentally disturbed person screaming on the subway about the end times, is equally valid. Young-earth creationists, flat-earthers, anti-vaxxers, and Q-Anon cultists are taken seriously, and have followings, because of postmodernism. Before postmodernism, these
people would have been roundly dismissed as idiots, and rational minds would set the record straight.
We went from there being three news channels that admittedly told a slanted narrative, to one where there are millions of "news sources" to choose from to fit your own personal narrative. And we went from one stifling, oppressive (usually religiously-driven) set of moral standards, to NO moral standards whatsoever, and complete moral relativism. Because no answers is better than one answer, and you must NEVER tell a person that they're wrong.
When I was a
kid I was foolishly taught that the sky was
blue, but now, thanks to postmodernism, I know that the sky is
whatever color a person believes it to be.