Because the .ORG registry is an American company. As disgusting as I feel agreeing with a AA on anything, they're probably within their legal rights here.

Not that they should be, mind. Domain registry needs to be a neutral ground and absolutely should not be subject to any kind of takedowns. A domain name points to an IP address - go after that. If it points to another country, your job just got harder, but that doesn't make it my job.