"American Men Novelists" didn't exist until Thursday, after Amanda Filipacchi wrote the first op-ed. "American Women Novelists" has existed since October.

I think that whoever created that classification system was the one who was really confused. If the list of all American novelists is too long, it can always be broken down by the initial letters of their last names.

Not to mention that some first names can be either male or female and that the genders of foreign names may be hard to figure out if you've never heard them before (there are plenty of American novelists whose families came from elsewhere). This would make it easy for Wikipedia editors to misclassify somebody.