Just because he is not the creator, does not mean he doesn’t have a role in its production.
I don’t think anyone who actually read the letter would be satisfied with Netflix’s assertion that Mr. Liu ‘is the author of the books, not the creator of the series.’
Either Liu is an apologist for crimes against Uyghurs or he is caving to the Chinese Communist Party’s doctrine.
Many authors whose books are adapted into live-action series are involved in the adaptation or production of their works on screen.