QADIYA, Iraq — In the moments before he raped the 12-year-old girl, the Islamic State fighter took the time to explain that what he was about to do was not a sin. Because the preteen girl practiced a religion other than Islam, the Quran not only gave him the right to rape her — it condoned and encouraged it, he insisted. He bound her hands and gagged her. Then he knelt beside the bed and prostrate