I read the Zizek piece and don't think we can get very far on the basis of this statement alone in comprehending Zizek or his defense of himself against Chomsky's comments about him. Their problem with one another seems to be a case of misunderstanding (despite their roughly common sociopolitical goals) of how to rethink a path toward radical social change and how deeply the subject of potential change must be thought. Chomsky apparently rejects the complexity of Zizek's thinking and writing as it includes insights into the human subconscious by Lacan and the limitations of human language as defined by Derrida. I'm fairly sure that Chomsky had his own confrontations with Derrida in the 70s or 80s. Post-structuralist theory in general is immensely multifaceted, so to understand Zizek it's going to be necessary to comprehend his sources. One scholar you linked to in part 3 of this thread, Adrian Johnston, might be our best hope as an entrée into Zizek and the speculative realists as well. Here's an interview with Johnston that you linked in part 3, and then links to two books by him, one on Zizek's philosophy. Reading the opening pages at the second link might be clarifying.
the interview we looked at earlier:
Interview with Adrian Johnston on Transcendental Materialism | Society and space
The first volume of Johnston's planned trilogy on 'Transcendental Materialism':
I like the quote by Dostoyevsky on free will at the front of this book.
Johnston's book on Zizek: