For whatever it's worth, I think your line of reasoning makes more sense. I see the difference between atheism and agnosticism as analogous to the difference between conclusiveness and inconclusiveness.

I don't agree with the "refuted yes" idea. In logic, "no" is not necessary equal to "not yes". For example, "not black" could be "white", but also "green". "God" does not have a well defined enough definition: it's very likely that God is not a bearded man on a cloud, but questions like whether omnipotence or omnipresence exist (and their correlations) are a whole new can of philosophical worms :)

He seems to be saying your thought experiment only shows reality is too complex to be viewed the same way by multiple people, and your claim assumes too much.