It’s on their weird about page

“The crazy thing is, despite all this, people still want kids. The economy and social challenges—are the real culprits for the drop in birth rates, not a shift in attitudes. Countries with austerity measures, like the US, UK, Germany, Italy, and Greece, have lower birth rates than Denmark and France.”

It seems to me that they are using population decline to go after austerity and NIMBYs