The rhetorics going here is awesome.
I mean, come on, we all know that if given a choice in adoption, the choice of "color" would be white over any shades of colors, probably along the line of white > pale asian > darker asian > black. This is especially true in the US, and I'm sure not too far from the truth elsewhere.
Yes, I'm in agreement that the situation is less than desirable, and quite f*ucked up, but human beings will do what please them the most. And if that means giving back a "yellow" Asian kid when one's desire for a presumably "white" baby is fulfilled, than so be it.
Look at it this way, imagine the shabby treatments this 7 year old Korean girl will get in the hands of these diplomats if they had kept her, knowing full well she's less than desirable and only fulfilling a temporary need for a child until the right one comes along.