I think the answer to this question is clearly yes.
Social workers got rid of the child's bio-parents, but they did not, and were not entitled to, get rid of all of the child's bio-relatives.
Is it not the duty of the child's adoptive parents to discover the circumstances of the child's removal from his or her bio-family and, unless there are very compelling reasons why the child should not be allowed direct contact with them, arrange contact meetings?
Due to the privacy of the family courts, any social workers will be unable to tell adoptive parents the details of how the bio-parents were alleged to have failed as parents.
Although there have to be reasons why a child was forcibly adopted, it isn't essential that the child was harmed before adoption. A fear that the child may be harmed in the future is sufficient.
I think adoptive parents will find that in at least 50% of cases the alleged and "proven" actual or predicted parenting failures will not appear very alarming and thereby not make contact meetings between the child and his or her bio-parents and or other bio-relatives inappropriate.