There are many reasons why a woman is a single mother, most of them sad ones. However, they often do not receive all the benefits which married parents do. This is not because the government wants to discourage them, but because that would border to encouraging single parenting.
As the article mentions, research has shown that children fare better in family units with one father and one mother. Why should it not? It was meant to be like that since the beginning. Therefore, to encourage single parenthood would be risking proper development of children. Yes, the country needs babies, but why risk giving the next generation a future less bright?
Looking deeper into this topic, often women become single parents because they had engaged in premarital sex. Were benefits extensively offered to this group, conservative factions of society might ask if the government is condoning such behaviour. Nevertheless, citizen benefits must be granted to the children, if not the single parent. The children might be facing a very uncertain future, so the government should do more to help those in need.