By "rationalism" I believe you to mean something like the premise that people are independent thinking entities who can, sometimes do, and usually should operate by taking an objective perspective and base their conclusions and actions on logic and (probably) evidence.

But you don't define it, so I'm guessing. I don't see a strong signature of Descartes & co here, and the philosophers you do mention were reacting in a large degree to positivism, which was more empiricist than rationalist.

I understand the argument that you've presented to be, "postmodernists etc. already explained why this is wrong: here are some names". You reference an individual/collective dichotomy, but given that even the most fiercely individualistic philosophers don't dispute that individuals at least interact with the context they find themselves in, you don't really express a clear alternative view. It's more: "There is an alternative view; details are left as an exercise for the reader."