Mrs Khan, you live in our beautiful country!  Please let me know which theory makes more sense:

#1 'Many felt that it was difficult to live as a Muslim in a hostile environment that left them feeling stigmatized and/or marginalized.' 

OR:

#2  Many  fell for the Islamic State propaganda and 'felt' it would be so much more exciting to be given machine guns, to be able to decapitate and kill , to drive tanks and cool jeeps in the desert......to have young Hazidi, Christian or Shia young women as sexual slaves ...