Honestly I don't think it's that deep.
She assumes on a subconscious level that most trans people are nice people who feel more comfortable conforming to the opposite sex stereotypes. And to be fair, I'm sure she's not wrong.
She also sees that trans people get bullied and real nasty abuse. Not just having to hear statements they don't agree with like Trans Woman Are Men or Some Trans Women are Autogynaephiliacs, but the sort of abuse some people deal out to anyone they think is different or breaking social rules. Actual violence, dirty name-calling, sexual aggression and worse.
She doesn't therefore see why we can't make an exception and pretend these nice people actually are the opposite sex.
She doesn't see the need to care that trans women aren't really women, because the pretending sits on top to make it all ok.
The only reason she can see someone would say no is that they don't like anything new or different, and therefore are basically the same as the nasty name-callers but hiding it better, so better to ignore them than dignity their hate by dealing with them.
And genuinely I think that's as far as it goes. "It's just a few people so why on earth is this such a big deal?"
I'm sure if you asked her whether men and women are just born with different types of mind she'd say of course not, that is horribly sexist. Even though that is exactly what she is saying every time she says TWAW.
She's just not thinking that deeply. Not thinking what agreeing TWAW is really saying about what women are. And not thinking through what changing sex based rights to personality-based rights means for women at all.