Because, rather than recognize that overdoing abstractions is a thing and reminding people that there is always reality out there that won't bend to your wishes, post-modernism (which is the term the GP used) tells people that there is no reality out there, it's all just human-created abstractions, and anyone who tries to push back because reality is just insufficiently post-modernist.
The only point on which all post-modernists agree is a refutation of meta-narratives (and to be explicit: "here is no reality out there, it's all just human-created abstractions" is a meta-narrative).
A very, very charitable interpretation is that you are maybe conflating it with Frankfurt School of critical theory, because it is also somewhat used/based on psychoanalysis (sigh) (latest postmodernists use psychoanalysis way less, also post-modernism isn't built on it, contrary to critical theory). Postmodernism is mostly post-marxism though, while critical theory is mostly neo-marxist imho (also, i don't want to be too critical of Frankfurt's school, i think most of their bad rep is caused by bad vulgarization/pop-science, most critics i read don't seems to understand why it's wrong either).
I do think that the reason most people conflate the two is because of an idiotic canadian psychoanalyst who can't read (or at least, can't understand what he read), who _clearly_ has no degree in literature or philosophy, and try to appear smarter than he is. He invent citations of the books, and sometime state that Derrida mean something when Derrida hismself wrote the opposite. 8th grader would do better and their reading comprehension assignment. He is wrong. Read and think by yourself.
It's not what post-modernists typically say post-modernism is. But I'm not relying on what they say it is. I've read enough post-modernism to form my own opinion.
> Read and think by yourself.
I have. See above.
Worse, it's the total opposite of one core tenet of postmodernism. It's very hard for anybody honest to argue that postmodernism has ametanarrative, when the only thing all authors agree with is that metanarratives are to be recognized and refuted.
> I've read enough post-modernism to form my own opinion.
Who did you read? Deleuze? Derrida? Foucault? Baudrillard?
I will always advise people to read Baudrillard first, I think he is somehow misunderstood in the Anglo world, but it might be mistranslations. Then Deleuze, then Lyotard and Foucault as Derrida is too dispersed imho, and way to complex, as imho you have to read his articles where he explain his books, alongside his books [edit: and to be fair I still don't think I really get Derrida, he's very recognized but to me he is very obscure, probably the weakest imho. I also disagree with a lot I understand from him, except his method, so that's might be my priors who prevents me to really getting it].
If anyone would rather read a novel to try to grasp what postmodernism is about, I think "l'Amour" from begaudeau is the latest (100 pages, really short and sweet), and the one that is still in my mind when I think about postmodern materialism.
You are relying what someone who earns money from making people angry about postmodernism say it is. Outrage culture and addiction.
Generally when you want to know what postmodernism is, you should read what postmodernists say. And if you want to know what nazism is, you should include readings of nazists.
