What's special about this ONE cue? Ummm... how about the fact that it can trick your brain into believing it's viewing 3D without including most of the others? I mean... you just said a 2D image doesn't have this one cue, but has the others. That, by definition, makes it special.

But your second paragraph show's me this is all based on confusion. The parallax cue and processing different images for each eye are the same thing, not 2 different things as you're implying. And that's the one of the cues that's NOT turned off.

I'm not defending what the author is saying. I just feel you should read the article again, because your statements don't seem to address anything said in the article.