"The highbrow novels, page-turning bestsellers, and one particularly inspired graphic novel after the jump all challenged the received wisdom that literature is or should be dominated by white dudes."

Yup, I think that pretty much says that they challenge it merely by existing.

You know, rereading this list, I think they picked books with an aim towards being as diverse in their list as possible. One with black characters, one with a lesbian, one feminist, one Indian, one Chilean and written in Spanish, one Iranian, one with a Japanese name on the cover regardless of the book's content...

Collect the whole set!

I hadn't realized that before, but it's pretty obvious now that I see it.