The best interest of the child doesn’t seem to be considered much in foster child cases. There are literally thousands of children in the US who are being subject to the same experience. It is unfair, but not uncommon. I was in the foster care system 30 years ago, and not much has changed since then.
As for this case, there is more to the story than what is in this article. Anna Mae was a foster child, not an adopted child. Every foster parent is well informed that the child can be given back to the parents or to other foster parents. The biological parents tried to get the little girl back for a long period of time, and the foster family fought them every step of the way. The biological parents are no doubt hurting the child by taking her away, but part of the fault lies with these foster parents. She was not adopted, and these foster parents have no rights to her at all.
They are doing irreparable damage to the child with the assistance of the court. That's why I preferred our court system when the biological parents and the foster parents were not the main consideration if both were found to be suitable parents. Only the best interest of the child was the determining factor, not who had better title to her.