It exactly means standing up, well, for yourself, and not relying on or waiting for others.
Stand up thing worked great in this story. I trust you that your relative could suceed in standing up instead of being treated as crazy bad women. A lot of it is residuum from old times when gender roles were different and some of both genders keep going old way.
Her existence does not excuse dudes who attempt to dominate women more them men. I did won those fights in the past, but the older I am the less I care about whether it was intentional or subconscious. It affects me all the same.
That is why stories like this are good to hear about - it is good role model for women lime your relative - to see that she can stop the dude, not to consider his interest and win.
Maybe you could show her the story to make her inspired for that.
This stereotype doesn't come from nowhere.
I found a video of this talk: https://www.youtube.com/watch?v=Er7qPv8jsZo
This "push to Hubeny's field of expertise" seems to start at 1:02:00, "let her speak" is at 1:05:35.
The OP's account is overdramatized and sometimes plain wrong, like the suggestion that Holt didn't let Hubeny speak at all for these three minutes (she had two long blocks) or that there was a dead silence after the OP spoke up (there wasn't). And that's a part of the problem: feminism is routinely being represented by individuals whose subjective perception of events seems to diverge from what others see. FWIW.
It fundamentally includes "in the face of adversity". And that means that you do it well knowing that there can and likely will be negative consequences. If you only do it under a guarantee of no repercussions, then you're not standing up...for anything, really.
If women have to learn to stand up for themselves as you imply they should, they need to find a way to hurt people who treat them the way they don't like.