Conversation so far:
Did William Shawcross right any books?
that had already appeared in the books by the Readers Digest and Francois Ponchaud.
What other authors  had reviews or responses ?
Ben Kiernan.
What was Ben Kiernan's response?
notes that Pilger did compare Pol Pot's Khmer Rouge to Stalin's terror.

Question: What happened after that?
Self-contained rewrite: What happened after Ben Kiernan compared the work of John Updike?