Pirate in NY to be tried

Ok, somebody help me out here because I slept through my bar exam for international law. Since when do people caught in international waters, or waters of a foreign country get tried in the U.S.? He isn’t a U.S. citizen and didn’t commit the crime on U.S. soil. Ok, I guess being on a boat from the U.S. counts as U.S. soil. So then why didn’t the Blackwater Ops get tried in Iraq? I understand that the military has special exceptions when bein charged for crimes on foreign grounds, but Blackwater is a contracted group. They aren’t U.S. military. So why weren’t they tried in Iraqi courts? That’s that bullshit.