They are brainwashed at a young age.
Yes ...I mean I remember the story about these 2 Norwegian Girls who went camping alone in some remote mountain & muslim men raped & beheaded them live on the Web.
Can't remember exactly what country it was.
Edit...
On 17 December 2018, the bodies of Louisa Vesterager Jespersen, a 24-year-old Danish woman, and Maren Ueland, a 28-year-old Norwegian woman, were found decapitated in the foothills of Mount Toubkal near to the village of Imlil in the Atlas Mountains of Morocco.