If the claim is that certain functions are what "generates" consciousness, then it's fair to ask whether any sort of functional arrangement will do, including writing stuff out on paper. I don't think it matters whether a billion Chinese are busy writing out 1s and 0s, or a computer is moving electrons around. None of that is conscious in my view, or at least I see no reason it would be.
I would sort of agree. Just avoiding first positing "well, even something silly would do" and then saying "well, that proves it's impossible 'cause it's silly". Then the argument is clearly unfair.
Your billion-person computer certainly would not appear to be conscious in real time - maybe that's why you just can't get your mind around the picture.
Can you imagine a billion people, none of whom who have never even heard of chess, writing out 1s and 0s, and thereby beating a grand master at the game? (in an appropriately slowed-down game, of course.)
What makes electrochemical and chemical reactions in a brain so special that you see a reason for them to create consciousness? Or is it a lack of complete understanding of those processes that makes you think so?