I believe it is not uncommon for people who have been adopted to feel some alienation, particularly if they are not told right from the start so it is not surprising that some cross-racial adoptees are unhappy.
I do hope that the care system is improving, but I have read the statistics about the number of 'cared for' (horrible phrase) children who end up in prison, on drugs, homeless, working as prostitutes, etc. or who are abused n some way whilst in care. No doubt some come into care already very damaged, but surely that just means they need even better care. We have all read about children who are shipped off to children's homes or foster homes hundreds of miles away from their extended family, or others who move as much as ten times in as many years.
I am not blaming the social workers, who, no doubt, do their best for all the children they meet, but something has very clearly been wrong for many years and I don't think we can just pretend that everything is right. Care is expensive unless it is given by the family and the amount a country spends on it is a fair indication of its level of civilisation.