To pick a further nit, the argument is more that qualia can't be engineered into an AI. If an AI implementation has qualia at all, it would be serendipitous.

That's a possibility, but not as I laid out the argument: if being conscious entails having qualia, and if qualia are all irreducible to purely physical descriptions, and every state of a turning machine is reducible to a purely physical description, then turing machines can't simulate consciousness. That's not very neat, but I do believe it's valid. Your alternative is plausible, but it requires my 'turning machines are reducible to purely physical descriptions' premise to be false.