@LittleGwyneth
The amount of insanely stupid shit I did at 15, I can't judge anyone else who made a mistake.
Even if you don't like her, she was born in the UK, she was a UK citizen and it is very scary if the government feel they can start removing people's citizenships as a punishment for bad behaviour.
If she came back to the UK she could be an incredibly useful tool for anti extremism work.
There's "insanely stupid shit", and then there's joining a death cult.
Getting drunk on Bacardi Breezers in a field, having unprotected sex, skiving school, taking pills bought from a Sixth Former, smoking, stealing from a newsagents are not ideal things to be doing at 15 - or at any age. Plenty do though, people make mistakes and we live to see another day.
Joining a terrorist organisation which bombs, rapes, beheads, stones, drowns, maims, drops from a height, kills and tortures men, women and children because of the colour of their skin, their beliefs, their actions, their sexuality, their country, their jobs, or just because they can is not even remotely on the same league as those things.
I could forgive my daughter of the things listed in the first paragraph, but forgive her for the rest? Not a chance.