It's not freeloading. It's a voluntary trade for value.
In any event, your logic is flawed. A person can easily be a net contributor over a lifetime without having children. And someone who has children, can easily be a net drain even after attributing some of the costs/contributions of the children (which may well also be negative).
In any event, your logic is flawed. A person can easily be a net contributor over a lifetime without having children. And someone who has children, can easily be a net drain even after attributing some of the costs/contributions of the children (which may well also be negative).