This isn't about people's race. It's about what the societies have contributed.
I am unaware that Toni Morrison wrote novels in something other than English either. I would raise up George Herriman, the author/artist of Jazz Age comic strip Krazy Kat as an African-American over the Clinton loving Toni "America's First Black President" Morrison.
I would agree with you that the article was about that if it weren't for the following quotes from the article:
the National Association of Hispanic Journalists, calling Dame Edna's column "an appalling display of bigotry." and all those who bear my kind of surname -- have been the butt of so many demeaning jokes and such debasing stereotypes
But on another, on that level that has had doors slammed, backs turned, hopes dashed, I also understand that too often satire masks prejudice and a joke can be just another word for discrimination.
I wonder what kind of reaction the Dame might have garnered had she written about the dearth of African-American lit other than Toni Morrison's.
Had the author argued that Edna's joke was not funny by giving examples of lit in Spanish that were great works and made the argument on Edna's taste in lit and debated that, rather than writing an article stating that Edna found lit in Spanish lacking because of the race of the people writing it, you would have a point.
The author is the one stating that Edna's comments were based on prejudice and bigotry, not content. The author is not arguing Edna's taste, she's calling Edna a racist. She should have taken the high road and couched the argument in your terms, rather than slinging racial accusations. In doing that, she would have made Edna look like an idiot, well, even more like an idiot.
The controversy was that there wasn't any Spanish language literature worth the effort since Don Quixote.
Name one place in the article where she rebuts Edna's contention that "There's nothing in that language worth reading except Don Quixote."