Well yes, why indeed? Jessica could have very easily asked Sally Ann to fill out a consent form. But she didn't.
Lots of survivors get in contact with Jessica and tell her their stories, as do other professionals, as she makes herself so available on social media, and Sally Ann isn't the only person whose story Jessica published without permission.
Basically, what seems to have gone on here is that Jessica has quite happily used other women's stories without seeming consent. She changed their names, so in journalistic terms, this arguably isn't illegal if they're not identifiable, and that's the line the publisher is taking.
But it's not ethical, nor is it informed consent. And when Jess markets herself on the basis of being an ethical champion of survivors, that's a problem as it's clear she doesn't care about the principles she writes about.
And then when she was caught doing it she tried to make the women whose stories she stole look like crazy, deluded nutcases. Classic DARVO.
Why does she do it? I don't know, I can't see inside her head. A lot of what she does doesn't make logical sense, the same as many abusive people.
Jessica often says the reason abusive people behave the way they do, is simply because they can. Maybe that's all there is to it. She usually gets away with it, and she doesn't give a fuck, so she does it because she can.
I don't know, why do you think she does it?
Sally Ann isn't the only one, she's just the one who has refused to back down in the face of quite considerable intimidation from Jess, her wife and other flying monkeys - sending the police to her door when Jess knew all along Sally Ann's was telling the truth about her story being in the book was a particular low.