Well, my experience involves much younger children and during the time of the legal proceedings to obtain a care order and then adoption, and I guess also that if you work for a charity providing adoption support for adults, you are likely to mainly meet people who have been negatively affected by adoption rather than those who have experienced it in a positive way.
The sorts of reports I sometimes have to read would leave people in no doubt that removal and adoption is absolutely the right thing in many circumstances. They are truly the stuff of nightmares.
Another thing- do the adopted people you speak to always get told the 'reason' for the adoption? I mean, the adoptive parents do obviously- they get to see the reports and stuff, but who then communicates this to the child? If I was an adoptive parent, I think I would think long and hard about how to frame that to avoid upsetting my child. It's certainly not appropriate to go into detail about abuse and things. Or is this information they have been told from tracking down their birth families?