Why do European Muslim girls look to Islamic State for marriage material?

FIVE hundred and fifty young Muslim women have left Europe to join Islamist groups in Syria and Iraq, and many of them have married fighters.
The women are well-educated, middle-class, born and raised in Europe. They were not deeply alienated from society, nor women who could have been easily radicalised. Why would young women leave London, Glasgow or Vienna to join a group that is anti-woman in its policies and behaviour? Why would they go to so much trouble to reach countries where their freedom of movement and expression will be severely constrained?