This kind of videos is why we need more statistical literacy in mainstream education because now we're drowned in studies and data because and people are incapable of interpreting it correctly. Family leave and universal pre-K have little explanatory power here. It's much more to do with the fact that women bare the children, while men can disappear into thin air after conception, making women the default caregivers. Because of the way society is currently culturally organised; men choose to be father, especially single fathers. Women are given this choice only with the availability of free abortions, otherwise this choice in imposed upon them. This assuming that sexual activity is a given, which it essentially is today because of birth control.

I'm sure you would find a similar difference if you looked at single mothers and "single mothers by choice", because a single father in most cases is a "single father by choice".