I feel that celebrities cannot be compared to ordinary people. They can basically do whatever they please because of the amount of money they have and because of their status in society.
However, even though we have children up for adoption here in the US, I feel that those children in the developing, third world countries need a home sooner than those here because of their risk for disease, lack of proper nutrition, lack of health care, etc.
But, if celebrities are going to those countries and paying the families for their children, this wouldn't be the best way to adopt. That is how slaves were gained; not that these children are being used as slaves.
I feel that most celebrities adopt from other countries because that gives them more "page time." By "page time" I mean pictures and stories in the news and in magazines. Not only this, but they are seen as more of a caring and generous celebrity, rather than just a money hungry, fame loving person.
Hope this helps...