Because the next generation belongs to everyone.  Families are entitled to a living wage based on family size, whether there is a question of abortion or not.  If you don't like that, take it up with Leo XIII and Pius XI.  

Abortion is not a choice, but neither does society have a choice on abortion unless it takes positive action at the national level to recognize personhood prior to viability.  Doing so without making sure these children are provided for is simply cruel.  There is enough responsibility in raising children without having to face dire financial need at the same time.