I am a searcher, but have not located my bmom yet.
In terms of people not searching or being receptive once found, I think that for many people the "birth child" is a painful reminder of choices/mistakes made in the past.
Sometimes in an effort to cope, people rewrite, justify or completely block memories surrounding painful/uncomfortable events and when "we" show up they are forced to face the truth/reality of it all. The deeper someone is buried in denial, the more negative the reaction may be. And it is human nature to place the blame on the person who brought them face to face with themselves, instead of taking responsibility for their own choices and behavior. Some people will go to great lengths to avoid confronting themselves/taking responsibility-even if it results in the emotional or physical harm of others. Some would even rather take their own lives than face the "truth".
I can understand not wanting to admit to yourself, much less others, that you've been a jerk, lied, made a mistake, royally f*** up, etc. But we are all so very human and cannot help but make a mess of things now and then. I guess I have never understood the extreme's to which someone will go in order to preserve their own reality - especially when it is easier in the long run to acknowledge it, take responsibility for it, accept the consequences and move the hell on down the road!
But then, what do I know?!
I guess the best way I have found to deal with this sort of thing (although easier said than done), is to accept that it is a reflection on them and not me, and try to let it go.
IWonderYou