Exactly.
Letting your kid die because you think god has forbidden blood transfusions is murder/suicide. Jehovah's Witnesses practice human sacrifice whenever they do this to themselves or to their own children. The Jewish God of War is a bloodthirsty deity and the Bible makes no secret of the fact that he does accept human sacrifice. They do it with the same strong faith that these Jihadis have whenever they kill other people or blow themselves up. These people think they are the good guys because their doctrine has them convince that they have divine permission to commit these atrocities.
If you want a normal person to commit hideous atrocities, all it will take is a nice fat dose of religion. When people begin believing that they are permitted certain things because they have divine backing, logic goes right out the window.