Wikimedia community member Liz Henry blogs here: http://bookmaniac.org/journalists-dont-understand-wikipedia-sometimes/ and does a little bit of digging into edit histories.
"Just from these three samples, it does not seem that there is any particular movement among a group of Wikipedia editors to remove women from the “novelists” category and put them in a special women category instead. I would say that the general leaning, rather, is to stop people who would like to label women writers as women writers *in addition* to labeling them as writers, claiming there is no need for Category: American women writers at all and that it is evidence of bias to identify them by gender. ... The sexist thing we should be up in arms about isn’t labelling women as women! It’s the efforts to delete entire categories (like Haitian women writers, for example) because someone has decided that that meta-information is unnecessary “ghettoization”..."