Young people joining IS, who is to blame?

Who is to blame for young people joining so-called Islamic State?
British police are still searching for three young girls from London, who travelled to Turkey believed to be on their way to Syria possibly to join IS. Shamima Begum and Kadiza Sultana, both 15 along with 16 year old Amira Abase left for Istanbul a week ago, and police are now in the country trying to trace them. In the UK a fierce debate has broken out over the failings that allowed the girls, and others like them to leave Britain and want to join IS. British police have said they had not found any evidence that the girls had been radicalised when they spoke to them last year in connection with another girl at their school that had left to join IS. Social media has been blamed for encouraging young people to join IS; their school has said access to social media in school was strictly regulated. There's been criticism of security services, airport authorities and parents - But where does the blame lie?
Picture: Met Police handout. From left: Kadiza Sultana, Amira Abase and Shamima Begum left the UK a week ago