OK, here are my two cents. I think there's blame enough to go around for everyone. Given the well-known corruption within Russian government, I'm sure adoptive parents (whether Russian or American) are not given the full disclosure on the mental/physical status of these orphan kids and that information regarding any physical and mental disabilities is hazy at best. So I'm sure there is at least a grain or many grains of truth in the adoptive mother's claim that she wasn't given "full disclosure". However, you simply don't take a 7 year old child, even if he is a sociopath (by no means proven in this case), and "return to sender" if for no other reason than he is a 7-year old child!!! If you have a modicum of sense and see these kinds of problems in your child--doesn't matter if he's biological or adopted--you find help for that child. That's what a parent does. This one clearly didn't.
So, to the extent there's blame on both sides, hopefully it will get addressed on both sides. Russian government needs to fix its process and transparency at the source and US authorities need to investigate this "mother" for her actions.
The saddest part in all this is that this event has the potential to disrupt many other adoptions of kids who, absent adoptive parents, have no future. Russian media has gone to town with this case making it an example of the "bad Americans". And granted, there are some and there have been well documented cases of Russian kids abused by adoptive American parents. But, who's adopting these kids in Russia? Almost no one because there is no culture of adoption in Russia. Yet, there have been thousands of successful American adoptions. So they don't want to give the kids to Americans, but can't take care of them themselves. Who suffers from this righteous indignation? The kids. The government just gets to score political points.