Has Mayer explained what's going on here?
I'm not seeing it, not in the original reports (in which Yahoo specifically declined comment) or in anything subsequent.
I can go either way on her decision depending on what her objective is for making it. For now, that's tabula rasa. This article is a good example: it's one author viewing the decision through the lens of a working mom. Okay: so the article reflects more the world-view and priorities of that particular author. All the commentaries do, in fact, because what they're missing is the world-view and priorities of one Marissa Mayer.
Sure, Yahoo needed a shaking up. A culture change. A refocusing and a reduction in both force and in breadth of endeavors. If a foundation of business is "find a need and fill it," it's not clear how the latter-day Yahoo is doing either. Mayer's Job One is to fix that. Okay, so how does this new policy fit in?
I'm a huge fan of the Five Whys technique. So far the why-ometer is stuck at zero.
IMHO, we (and the pundits) have insufficient data for analyzing this move, much less criticizing it.
But Mayer and Yahoo can be criticized for not getting ahead of this story. From page 202 of Scott's Big Book of Pithy Pronouncements, Milton's Law states: "In the absence of information, people will naturally assume the worst." Insofar as that's in play, it's potentially damaging and difficult to control. In that regard, I'm not impressed.