It’s tough to say. Most of their assertions end up stating that it’s Marxism, so they mostly aren’t rational or clear about what they are saying. If there is a coherent, accurate, referenced, nuanced conservative concern about post-Modernism that points to the authors you reference, I haven’t seen it. But it’s a bit of a morass wading through conservative ‘though pieces’ these days, so it’s also possible your point is valid somewhere over there.