The point I tried to make that having children is not equal to having cake - from the point of view of the society in total it is necessary as is eating and sleeping. The need is for the society. To maintain a healthy corpus the society requires children as people require food and sleep. Therefore it seems rational to me society participating in child rearing in form of financial support.
It's a political view. The way I see it a functioning society is a resource and a substrate for companies. A company that does not give the minimum support for family life of their employees is effectively reducing the quality of the society where the particular center of operations is situated. To me, it's a similar logic as to why there are environmental controls for companies and other incentives against negative externalities.
