alot of girls can act that way saddly.
Men and women alike can act that way, but in the cases that they do, it's for different reasons. I suspect that while men who hit women are volatile enough to fail to consider that they'll be punished especially gravely for it, women who hit men are either stuck in the frame of mind that they're "weak" (and therefore their violence against a man, "who is strong", doesn't "matter") or they bank on how that's the prevailing sentiment-- even with the man they're hitting, who can easily gravely injure her if he retaliated. The latter has the assailant holding a strange contradiction: they rely on a goodwill they pretend isn't there in order to complete their action unscathed.
This is probably a throwaway moment in that it's likely only used to dynamically introduce this new guy, but thinking about it makes me think about how less seriously we often take female violence in general, especially when it's directed towards a man.
In this particular case, It's true that it's an entitled reaction, but my interpretation is that she was looking at a way to hurt him because she was hurt by her misunderstanding of his intentions (which she interprets as "being hurt by him").