[armoredkitten]

Yes that stuck out to me as well. The author seems to be setting up a straw man, as if people are arguing that the brain can't distinguish between a line drawing and the real thing (or a line drawing and a photograph).

The other information isn't necessarily discarded. It's just used to identify that this is a line drawing and not the real thing. It's still remarkable that just the lines themselves (I make no claim as to whether it really is edge detection or something else) are still enough information to be able to identify the representation, but it doesn't mean the brain is discarding the other information.