Not sure how to concisely explain how female only events aren't similar to like, white only events

If she wants to use race as the comparator it is a more accurate comparison to say:

Should a white person (oppressor) who identifies a a black person (oppressed) be allowed to attend a black only event as they are in a minority group (the group being those of one race who identify as another).

This. It’s about the power dynamics, the oppressed group are entitled to space away from the oppressing group.

Yes agreed. This is such a shitty argument. False and disgusting.

Men are womens' oppressor group. White people are black people's oppressor group.

Your friend sounds spectacularly dim.

Her analogy would be closer to the truth if she said "women-only spaces are similar to black-only spaces". And many of us would perfectly well understand why black people may want or need safe spaces that do not contain white people.

"well what about white people feeling safe?"

That's a bit of a racist comment from her.

One sex impregnates, the other is impregnated

Yes clearly not all etc etc, but that is the difference.

A women only event included all women; black, white, gay, straight, old, young, able, disabled, religious, atheist, left, right, rich, poor...you get the idea. No minority is excluded, even women with trans identities may attend. Men are not a minority. They can organise their own events.

I'm no expert but I would be saying that it's more like 'Blacks only'. Women are an oppressed group and have been forever. Allowing women to meet on an environment free from those responsible for the oppression is essential to allowing us to support each other and learn to confront the oppression.

Because there is a clear biological difference between men and women.

Without protections, women can be raped and forced into pregnancy. They are weaker. Laws are needed to ensure that they can have equal rights.

This is not the same with regards to race.

It’s racist, black women are women. Trans women are men.

I love that US women are on MN. Seriously. All women should unite!

I don’t have a great answer but in this equation it is like women are the non-whites. Whoever holds the power, they are excluded. And as Trans women are men then they hold the power (traditionally) as they are men. Saying trans women should be allowed in female only spaces is like white men should be allowed in a black men only space. Why would they want to? It’s strange by its very nature.

In UK, it's "biological women only; not biological men". It's based on sex.

Saying biological women only is excluding all men, whether or not the men identify as women.

All biological men can be excluded for the safety, dignity and privacy of biological women.