Not to step out of my lane (which I’m probably doing by saying this and I’m sorry) but this is what it means to be strong, a girl and a character.
It’s not being the emotionless. man-blood thirsty hollowed-out-shell that Antis were demanding back in the first two seasons. Usagi’s going through a painful time, having met people who she just knows are supposed to be her allies who are actively trying to avoid her. She can’t understand it, and they won’t even talk to her about it, so she’s just left to wonder, and to be hurt.
But regardless, she doesn’t wallow in those negative feelings. She has a duty, and in the face of it, she decides to put those things aside because she knows she needs to be strong to protect herself, those who she loves and her planet.
It’s not being solely focused on her friends rather than her lover, it’s not about dismissing the traumatic memories from another life hitting her all at once while once again she’s a witness to the murder of her lover, and it’s definitely not about girls murdering innocent men just because you didn’t get your expectations met and decided a show was misogynistic for it.