Just because marxists hate postmodernism, doesn't mean that non-marxists can't hate postmodernism.
You are arguing from an ideological bubble where you assume that your critics don't understand what they want.
From an agnostic viewpoint, it is clearly visible that the overlapping effects of marxism and postmodernism are the deconstruction of traditional gender roles, family roles, architecture, socioeconomic roles, and the restructuring of traditional culture as a whole.
Regardless of whether or not _you_ hold any value for those aforementioned things, it is clear that there are other people that value them, and thus they will argue against marxism and postmodernism.
Of course, those same people will lump together postmodernism and marxism into the same box, because they both stand against what they believe in, just as how liberals will lump together fascism and communism - to the layman, all enemies are the same.