>Indeed. This one is plainly saying "I can't work up any interest in doing anything for this article >except to zap it. You want to keep it, you do all the work." 

To be fair:

1. the assumption has always been that the burden of proof of notability is on the person asserting or defending it. WP:FAILN doesn’t require that an editor doubting notability look for sources themselves; it just suggests it as one of several options.
2. The editor in question prodded it rather than nominating for deletion; this is meant to provide exactly this sort of informal process as a remedy for perceived deficiencies (I would have preferred he use {{notability}}, the gentlest and most AGF way of raising these concerns, but even still a prod is not as in-your-face as an AfD nomination).
3. I admit that on the face of things an article that asserts as its subject’s chief claim to notability that she was married to someone who became president of the United States after her death is that I would like to see more first. Looking over its history, the article dates to 2004, and was expanded shortly thereafter, back when we didn’t require sources so much and a lot of articles like this got created. Perhaps improving existing articles about women should be as much a focus of our editathon events as creating new ones.

>Now I want to know what other women's history articles are on the hit list like this, to be able to forestall the deletions within the short window of time allotted.

Perhaps you could do the AGF thing and engage the editor on his talk page. His recent editing history does not suggest to me that he’s engaging in some sort of systematic prodding of articles like this one, rather that he’s making a lot of housekeeping edits to American political biographies and perhaps saw the Nell Arthur article (possibly in the context of looking at other Presidents whose daughters (or in one case daughter-in-law; see [[Priscilla Cooper Tyler]]) have stepped into the First Lady role) and wondered why we had it.

Daniel Case