Edam, I have repeatedly accepted that there must be miscarriages of justice and for the people involved they are heartbreaking and I understand people who have experience of them campaigning to improve the system to avoid them where-ever possible. But the OP has repeatedly started threads implying that this is common and has made some extraordinarily crass statements about how adoptive parents communicate the facts of their adoption to their children and has linked a painful and personal thread started by a family member to a national newspapers website as an example of how unreasonable we adoptive parents are and as a result I have lost any ability to empathise with his position.
Most adopters by nature know a great number of other adopters - certainly I do myself and I know of not one case from the UK system where an adoptive family is not dealing with either with effects of severe physical and/or sexual abuse or with a sibling who has suffered such. As far as I know my experience is not unusual and that indicates to me that the vast majority of cases are really very sad but straightforward - such people should not be allowed to parent any child and a child deserves to grow up being safe and secure within their family unit.
It is not that I can't accept that miscarriages don't happen or that adoptive parents can be as scared and defensive of losing their child as any other parent, I can. But what do you (or OP) want us to say "Yes my child should be allowed contact with their birth parent despite the immense damage done"? Or should we pretend that there was no atrocious parenting and that contact will be beneficial to a child regardless of what issues of attachment or separation anxiety they are going through.
I would love DS to be in contact with birth family. It would tear me apart but I would love it. I also think he would struggle immensely with it - he has separation anxiety and has to be managed very carefully, he gets very distressed if anyone calls me "mummy" but him even in jest and I can't imagine how he would deal with a real birth parent sitting in front of him. He understands he has a birth mother he just doesn't want to talk about it at all at the moment.
We cannot ignore the real issues we face day to day and pretend that the situation you and the OP describe are relevant to us because they aren't.
Please read some of the other threads the OP has started and his later comments (he also posted as Melvin something) because you may then understand why we have no real wish to engage anymore. In fact I wonder why I'm even bothering now.