As I understand it, the point of the scenario is intended to be an argument against physicalism. Qualia are claimed to be nonphysical, because Mary knew "every physical fact" about color and human color perception, but still (it is claimed) learned something when she saw red for the first time.

Dennett, if I undersand him correctly, argues that the "knowing every physical fact" is a very strong hypothesis, which the exposition of the scenario doesn't pay enough attention to. With so much information and comprehension, Mary is not very much like a human; our intuition that she would say "wow" is not trustworthy.

In particular, I don't think that we actually disagree - your posts seem to come from a physicalist, rather than dualist, conception of the world.