It doesn't sound to me like he's making the argument that you think he is. He's saying that being able to manipulate Chinese symbols per some instructions isn't

It doesn't sound to me like he's making the argument that you think he is. He's saying that being able to manipulate Chinese symbols per some instructions isn't sufficient to demonstrate understanding of Chinese. Okay, I agree. But seeing someone manipulate Chinese symbols doesn't mean that you can assume they're simply following instructions without understanding the symbols either, does it?