I mean, she lied about liking transphobic tweets:

On one level, my interest in this issue has been professional, because I’m writing a crime series [...].
When I started taking an interest in gender identity and transgender matters, I began screenshotting comments that interested me, as a way of reminding myself what I might want to research later. On one occasion, I absent-mindedly ‘liked’ instead of screenshotting. That single ‘like’ was deemed evidence of wrongthink, and a persistent low level of harassment began.

Sure, Joanne. "My interest in this was only professional, because I was writing a book ~~where the serial killer is a man cross-dressing as a woman that kills other women~~". We know how it ended.

She then proceeded with a very weird anti-trans statement:

When I read about the theory of gender identity, I remember how mentally sexless I felt in youth. [...].
As I didn’t have a realistic possibility of becoming a man back in the 1980s, it had to be books and music that got me through both my mental health issues and the sexualised scrutiny and judgement that sets so many girls to war against their bodies in their teens. Fortunately for me, I found my own sense of otherness, and my ambivalence about being a woman [...]; it’s OK to feel confused, dark, both sexual and non-sexual, unsure of what or who you are.
I want to be very clear here: I know transition will be a solution for some gender dysphoric people, although I’m also aware through extensive research that studies have consistently shown that between 60-90% of gender dysphoric teens will grow out of their dysphoria.

"I felt non-binary too, but I'm not trans, so you aren't either!".

For reference, desistance is a real term that refers to people who changes their mind about their gender dysphoria, and, although further research is still needed, she is probably citing real sources. It's also strange to insert that knowledge in a post where she's supposedly trying to convince people that she's not a TERF, among the "five reasons she's worried about the new trans activism", whatever that means. "I don't hate trans people, but anyway, they aren't real and you are preying on children".

She then ended her wall of text by alluding that all trans women are actually men who want to prey on women (never mind that, if a man wanted to become a sexual predator, he could just... Do that, instead of faking gender dysphoria? Like, a man who wants to sexually harass someone isn't stopping at the "girls only" sign. He's not a vampire). But hey, before that she said that she cares about trans women, so I'm sure it's just a misunderstanding.

So I want trans women to be safe. At the same time, I do not want to make natal girls and women less safe. When you throw open the doors of bathrooms and changing rooms to any man who believes or feels he’s a woman – and, as I’ve said, gender confirmation certificates may now be granted without any need for surgery or hormones – then you open the door to any and all men who wish to come inside. That is the simple truth.

That's the simple truth of a person who should really talk to their therapist about her trauma instead of writing bullshit online.

If agreeing with known transphobes, erasing trans identity, and putting trans women and sexual predators on the same level isn't transphobic, I really don't know what is.

I hadn't read this before, and I am honestly shocked that this is the what the uproar is over. This isn't a call to action to hurt anyone. It is basically a statement that there is a difference between a transwoman and a woman, that distinction needs to be made, and this is mainly due to society rushing to a solution without due diligence. This is not 1/100th of what it has been made out to be. If this is all it takes for someone to never want to associate with someone else, then I don't think he should associate with anyone. Everyone is going to differ from your opinion on one topic or another, you can't escape it.

No This is it, after a relatively lengthy twitter conversation she ended up writing this blog post.

And the anger and vitriol boils down to "why do animal rights activists throw paint on rich ladies wearing fur, because bikers in leather jackets will punch you in the mouth".