You could argue that the Johnsons should have given Sam back when they learned that Vietri had popped up. Those acts were not the Johnsons' fault. Yet they are being asked to take the responsibility. What a cuckoo, backward world. The Baby Sam case and others like it get the headlines.
Exceptions always do.
Nose around the world of adoptions, and you'll find contested adoptions are rare. You'll also find that birth fathers often deny paternity or don't want anything to do with the child. Now and then you'll find a birth mother who can't wait to unload the baby or uses adoption as a way just to get money. If Chris Vietri truly didn't know that his biological child was alive, he does have a legal claim on him, under Florida law. But Vietri's right and his responsibility are not the same thing.