While your points may be valid, they don't apply here.
It seems the child was not abandoned but swept up with the father's criminal problems. When the father was aquited the child should have been returned to the parents. Instead (the article does not say intentionally) the foster parents essentially tried to steal the child.
This happens time and time again with adoptions by force. The lawyer is generating legal fees by playing on the emotions of the foster parents. If we apply the logic of the adoption lawyers, just steal the baby of your choice and as long as you are a better mother or father you get to keep the child!
If the biological parents put the needs of the child first and not their own selfish ones, they would allow the child to be adopted by the foster parents. Any way you cut it, that's what's best for the CHILD. The bottom line is that in the end for the biological parents it was about winning. Sad.