It's pretty clear they just wanted to provide some closure to the biological parents, e.g.

But it was important to us that the birth parents knew their daughter was adopted by a family who love her very much and provide her with a good home

And it seems quite unlikely they wanted to provide anything more than that. So I think if you're going to call the parents a cunt for, as you put it,

First they established contact with the parents, promising them more news. THEN they abrubtly cut off all contact.

Then it's pretty obvious why I'm calling you a cunt and arguing over it. I also completely reject your ridiculous premise that both friend, and parents were arseholes.

I think providing them with some information that their daughter was safe and loved, almost undoubtedly with no promise of future communication from the parents themselves, is the complete opposite of being arseholes.

Stop being a cunt, man. They tried their best to do right by everyone, give them a break.