Unfortunately the system seems to always believe men are the only violent ones even when we know full well there’s some really bad nutcase women who not only hit but put away men....and their own children.
It’s obvious Laundrie killed her. I would infer that he did so in the heat of an argument, in which she did or said something that sent him into orbit. He simply didn’t have the self-discipline to walk away BEFORE he actually killed her.
Men tend to use fists but women tend to use weapons like knives and blunt objects (frying pans, lol). Domestic violence against men is as big a problem as against women. Many men are too ashamed to report it. At least according to the last data I saw on it.