The poster is shocked because people's (self-estimated) ability to afford kids has gone down, leading to a larger number of people who want kids to stay childle

The poster is shocked because people's (self-estimated) ability to afford kids has gone down, leading to a larger number of people who want kids to stay childless. They are not saying that people wanting kids is a bad thing. Many people assume that people have less kids because preferences and lifestyles have changed, leading to headlines like, "Millennials don't want kids" (And maybe in the same vein, "Millennials are killing cars", "Millennials want smaller homes", etc.)