So you admit she is afraid of trans people. That makes her a transphobic.

I am very aware of her past and sexual assault history. I too have been sexually assaulted, by men, as have 25-40% of women. I too am gay, I’m in a long term lesbian relationship. I know people have actions and beliefs that come from trauma, I’m a trauma survivor myself.
Trauma and healing leads to lots of things. Fear, which is a natural trauma response, can often lead to hate. I do think trauma is important to recognize, but we need to be careful because it easily can lead to hate. Not a single trans person has anything to do with the man that assaulted JKR. They aren’t him.
They shouldn’t be held responsible for the choices he made to assault JKR.
As a sexual assault survivor, I had similar opinions about trans people before I actually knew any. I live in an area it’s legal and expected for trans people to use the bathroom with their chosen gender. I routinely share a bathroom at work and a locker room at my gym with trans women, and have done so for years. It’s totally fine. There’s no weirdness at all. Actually trans people have been using their chosen bathrooms for decades (since the 80s) and it’s only now freaking people out.

50 years ago we were having the same discussions with black and Asian people using the same bathrooms as others.

Anyway, I’m not arguing points. Regardless of someone’s history justifies their fear or not, being afraid of trans people is literally the definition of being transphobic. I got bit by a spider, I am an afraid spiders, especially black widows. I have arachnophobia. I won’t deny it. I don’t go around arguing I’m not arachnophobic purely because I have trauma with spiders thus my fear is “justified.” “Justified” fear is still fear, plain and simple.
She’s afraid of trans women because she has a bad experience with a man. So what, she’s still afraid of trans women. She’s afraid of trans women, justification or not, that’s a transphobe-by literal definition.
I was sexually assaulted by a black man, does that mean it’s okay for me to expect laws on black people to be stricter? Does that mean the rights of black people should be up for public debate? Sorry, but trauma does not enable you to make decisions about others.