A woman takes the last name of the person who has publicly and privately taken responsibility for her health, safety, and well-being. Traditionally, it was recognized that a woman with a young child/children was vulnerable, and lacked the resources to provide for herself and her young ones, especially when they were newborn or very young.

Now, with birth control and with no social stigmas against children being born out of wedlock, and women having little or no compunctions about letting strangers who run a daycare raise their kids...the women are starting to wonder why they are changing their names.

This is more attempt to tear down all the structures that led to such widespread prosperity, and cultural stability.

TL;DR: commies gonna commie.