Is bringing up old stuff a friend did to hurt them even though they were going through a rough time and has changed since then callout culture? I've done this repeatedly with an old friend out of rage over her past actions and I wanted to pass my hurt onto her because I couldn't see her for anything than her past actions and ended up believing that she was incapable of change.
that's not callout culture, no, but it is being a shitty friend. it's also a red flag for abusive/manipulative tendencies, since many abusive relationships involve that kind of dynamic. (constantly bringing up past mistakes, making the victim feel guilty and obligated to make up for those mistakes to an excessive extent, making the victim feel like no one else would put up with their mistakes except for the abuser, etc.)
i'm definitely not saying you and your friend are in an abusive relationship, those are far more complicated than one single worrying behavior. however, i am saying that that behavior is unhealthy and unproductive and it needs to stop if you two want to remain friends. unfortunately, if you two can't work it out and the friendship has too much emotional baggage to stay stable, it needs to end peacefully rather than fester and become toxic to you both.
allow me an anecdote, if you will.
my best friend/queer-platonic partner and i nearly ended our relationship a couple years ago over something like what you're describing. he became friends with and started hanging out with a group of people who loudly, proudly, and openly bullied me and my other friends. it created a lot of tension as i tried to understand why my best friend was cozying up to antis, and it became harder and harder to defend him to my other friends as we all faced the brunt of the abuse being hurled at us.
now, my qpp had his reasons for doing what he did. as it shook out, he was trying to infiltrate the group so he could be a good influence and try to get some people out of that mindset. but that didn't mean that what he was doing wasn't hurting us. eventually i had to come out and tell him that if he didn't stop hanging out with those people, then he and i would have to part ways. we lived together at the time (and still do) so it wasn't as simple as blocking him on discord and being done with it. i'm actually very glad for that. it forced us to have a heart-to-heart about our feelings and my pain and his motivations, and at the end of it he decided to stop associating with and supporting the bullies because our relationship was more important and he didn't want to keep hurting me.
does that mean he never hurt me? does that mean he didn't willingly pal around with antis who were personally harassing me? no. but he listened to me when i told him what he was doing was hurting me, and he changed his behavior.
now, years later: i don't bring it up anymore except on occasion, in passing, usually as a joke. there's some distance from the incident and it's not as painful anymore. i don't hold it against him. when we argue - which we still do, as every couple does - i don't bring it up to wield as a weapon against him. to do so would force us both to constantly relive that horrible period of time where we almost lost each other.
you don't have to forget what your friend did or said and how it hurt you, but if you can see that she's changed, you need to let it go. if she's never formally apologized, you could ask for one as closure. if she has, accept it and forgive her and move on with your lives.
(you should also apologize for your behavior, even if she hasn't called you on it yet. you fully recognize that what you're doing to her is hurtful and yet you continue to do it, you know that's wrong.)
i wish you both peace and luck.