Sorry, but I see a big contradiction between this statement:

They're nice and we all get along great.

And this one:

But there's one freshman girl that, while she's normally pretty quiet and introverted during our gatherings, will occasionally speak up about beating up whatever "villains" are tangentially related to our discussion. "Kill TERFs", "Punch your local TERF" etc. etc. Things of that nature.

That's what passes for "nice" nowadays? For a woman to say this aloud in front of a gathering of women - a group of women she presumably wants to curry favor with and gain the approval of - sounds sociopathic to me. This is not a person I'd be welcoming into any club I belong to. Good lord, what might she say when representing the sisterhood in public? I also wouldn't want to have her living with me and other women in shared intimate quarters.

The fact that you say you "all get along great" with a woman who has no compunction voicing aloud anti-social sentiments that in most settings would be considered unspeakable and way beyond the pale is mind-boggling to me. What is the name of your sorority - The Heathers Society for The Promotion of Murder of Girls & Women We Don't Like?

And I don't get this:

when she does it, someone might nod sympathetically or something, but we move on quickly...

You have sisters in your sorority who nod sympathetically when a recruit advocates beating and killing women coz the recruit assumes those women to have views she doesn't like? Really?

Nor do I get this, coz it seems like projection, presumption, and going way overboard to give someone the benefit of the doubt so as to avoid being critical or confrontational:

It really feels like she's just doing it because that's what she hears from other woke LGBTQQIAAP+ groups around campus, and she's used to needing to parrot that stuff around those other groups to fit in better, because they reward that kind of behavior.

OP, doesn't your sorority have a code of conduct? If so, does it really say it's acceptable for sisters and pledges to openly call for the assault and murder of women whose views some of you don't like?

If your sorority doesn't have a code of conduct, perhaps it's time to get together and consider making one. And perhaps a good character-building and community-fostering exercise would be for each one of you to have to do a short presentation to the rest of the group about your interpretation of this famous internet saying that started circulating a couple of years ago:

“What you permit, you promote. What you allow, you encourage. What you condone, you own. What you tolerate, you deserve.”