Having made or worked on quite a few films, I can assure you that they don't watch themselves, and that if one has done one's job correctly they just repeat the exact same behavior every time. I would be quite interested to see a movie in which one of the characters decided to do something different from the previous viewing.
Pierre Menard could have made a movie.
But even leaving that aside, and assuming for a moment that replays are indistinguishable (and one can enter the same river), would you accept that a movie is reducible to a photographic film chemistry?
Oh sure. I'm disagreeing with the idea of it being an automaton qua having some ability to adjust to interaction rather than being static like a book.
I don't know why you leapt to this thing about the film watching itself. The author did not ask me to assume this.