You seemed to have missed one "little" detail Bowser.
"The Mastoi tribe called a meeting of the tribal council, which ordered the girl to be raped to avenge their tribal honor. The teen-ager said she was taken to a hut and assaulted as hundreds of Mastois stood outside laughing and cheering."
Not only did the tribal council order the rape, but HUNDREDS of people watched laughing and cheering. The case you sighted was of a lone individual, there wasn't a government mandate or huge crowd of Americans outside urging him on.