I don't have any brilliant insights about this, I'm afraid -- I am lucky to not have had an abusive childhood, and when friends and potential partners have disclosed their family issues to me, I can't relate to reacting in the way this person did.

I just wanted to say that WOW this woman is awful. I'm glad you didn't have to waste the time trying to travel to meet up with her.

I guess maybe one thing that comes to mind is, if you answer with, "That's complicated" and you find the person pushing you to talk about it before you're ready, that's already a sign that maybe they are not going to be great at dealing with this. I know it's tough but I think you should feel confident and ok about standing firm on topics you're not ready to discuss. That doesn't mean that even if she gives you the space, she's not going to be insensitive when you finally are ready to talk, but it seems like a reasonable first pass. When friends I am not close to yet say things like "It's complicated," I leave it alone until they're ready, and there's really no reason not to do that if you actually remotely care about someone as a fellow human!