There was a Reddit post about this not too long ago. A mom of an adopted child posted. She described how many parents, including her, had no idea what they were getting into adopting a child coming from a troubled background. Things that child did, as she described it, were very disturbing, and would bring many people to their brink.

So one can argue it starts with ignorance. People think raising a child is a walk in the park, playing baseball outside on the front lawn, going to football practice and all the nice stuff people see on TV.

From there it moves on to lies. Overseas adoption agencies can be very shady. They want to close the deal. They will hide and paper over medical histories.

Then once a child with severe psychological issues (some which manifest themselves 6 or more months later only), become apparent. The despair starts to take hold. Then someone knows someone who heard about his online "marketplace" and so on. It puts an idea in their head.

Then, a loophole in the law is used. The idea behind having laws to transfer guardianship is to get kids to stay with family members and to keep them out of trouble if say immediate parents create an unsafe environment. Unfortunately that same provision the way it is written allow pretty quick transfer of guardianship and it is exploited in this case.

I would want to believe some of these children end up in home that try to help them, parents who know how to handle such issues better, but unfortunately quite often that is a market for predators looking for victim. The article has a few disturbing details on that, I won't reiterate here.