Do you tell a widow that she is being negative, ungrateful, angry, bitter, resentful if she still tears up or struggles with grief or sorrow over the loss of her first husband even after she has happily remarried? I would hope not.
Although adoptees--similar to a widow who has happily remarried--may have gained a family, you must keep in mind that the only reason they have so-called gained a family is that they first LOST everything. And when I say everything, I mean, everything.
They have lost their original father, mother, grandparents, siblings, extended family. They have lost their language, culture, and country of origin. They have lost any connection whatsoever to their beginnings, to their identity, to the most basic elements of who they are. They have lost any knowledge of what happened and why.
I think adoption is very difficult to understand for anyone who hasn't been through it- especially transnational & transracial adoption which have their own complications and can make it obvious that you aren't "really" your adoptive parents' child/ren. This was a really good way of explaining why adoption hurts, even if you love your new family.