Right, but you could have given up the child. The child would then either be raised as a ward of the state or adopted by another couple. Children raised by the state generally have inferior life outcomes,* so by raising them yourself you save them from this negative-expectation fate.

Conditional on not giving them up, you have this legal obligation, but you do not have this obligation unconditionally. If praise is warranted for good acts that are legally optional, you deserve praise for not giving up your child.

*though people might reasonably argue that is more because of genetics than anything else

edit: formatting