Postmodernism is a cargo cult. It seeks to duplicate the form of rational inquiry, while lacking the substance. It's children dressing up in parents' clothes, and complaining about things they don't understand, like taxes and sciatica, for no better reason than that is what they see adults doing with their time.
Monkey see, monkey do.
Postmodernists believe that if they make their terminology sufficiently obscurantist,
sesquipedalian, and circumloquatious, nobody will notice the lack of substance. To a large extent, they are correct in that belief.
Some postmodern philosophers (like Baudrillard) are beyond help, while others (like Foucault) are largely salvageable. This must be judged on a case-by-case basis, but not without boots to wade through the exceedingly thick bullshit that permeates the entire idea-space.
When you start getting to ideas such as "science is sexist because it probes the natural world (which is the sacred feminine) against its will, thus committing rape" it's time to throw the document in the fire. It's important to leave a lot of room around the fire, though, as you've probably
underestimated how much pomo literature is totally worthless.
Jack: I just learned about postmodernism in college, and now I totally believe in it, and self-identify as such.
Jill: You and
every other gullible sophomore
looking for an
intellectual family where you can't possibly be wrong, you fucking latte-sipping coward.