Tbh Im not the only one making logical leaps here. Its not like she lived in some 3rd world hellhole where information is limited and controlled, isis was literally one of the hottest topics at the time, their attrocities well documented on all major news networks.
Also I love the part where you say she was just used as a concubine. I seem to recall you being a muslim, so you should know what the state of womens rights are in places where fundamentalist islam is practiced. How do you think people are groomed by islamists? Do they use human rights to lure people in, or do they use islamic norms and texts? She knew full and well how her life would be like in isis land. Do you really think she would have had a change of heart if isis won?
I can be lenient on many stupid things teenagers do, but what she and others like her, male and female did, is beyond stupid.