I think it's fair she should come back and face the consequences of her actions. She was radicalised in the UK and went off to the middle east as a 15 year old girl with her head full of shit. She was forced to marry some random bloke who was killed, had 3 kids, all of whom died, and on a humanitarian level, that's an awful lot of crap to get your head around when you are in your teens.
She has said she'll face the weight of the courts if she returns to the UK, and she will be an advocate of all that's wrong with being a radicalised teen.
Yeah, she's been through the mill, and she was a young, impressionable woman when she went out there. I think it's time to accept the fact she has grown up, realises her mistakes, and let her come home.
We've all made stupid decisions as teenagers at some point, but as we have grown older we recognise that and it doesn't define us for all time.