Postmodernism in philosophy is associated with rejection/skepticism of common narrative (eg reject absolutism in Marxism/capitalism/etc). He claims he understands the common trends (in “infoops”) and goes beyond them, which I guess is his justification for the word choice. I agree it feels more of a flex than an actual precise use of language.
And my favorite simple way to define it is:
modernism - post industrial revolution enthusiasm about humanity
postmodernism - post ww2 depression about humanity