"I think most women are accustomed to living with the presence of male violence, even when it’s not explicitly visible, but I’m also interested in the wounds a person carries around that are self-inflicted, or at least self-aggravated." The author herself commenting on the underlying violence in the story, and I've been saying this same thing for ages. Nature versus nurture being always brought up, yet violence through nurture is very much internalized in women, especially past college age.
That is why in my 20s my characters lashed out quickly, and my stories were short (like 8-900 words short), but nowadays at twice that age I'm more thoughtful about these indicators, how likely it is that they injure themselves instead of somebody else. Yet I'm also from a socially conservative culture, so I could relate to your Italian American character, sinclairfan, as there's a point where temperament, regardless of age takes over, and reason steps in which tells her that that bitch does not belong to their circles, to their "tribe", the usual repercussions for acting out don't apply, so a fight erupts.