" "Good for her" is an expression that congratulates women for striking back against men, women, or a society in general that has sought to hold them down, even when the retaliation is violent or excessive. The phrase originates from the comedy series Arrested Development where eccentric alcoholic Lucille Bluth congratulates a woman on the news for allowing her car to roll into a lake after she "couldn't take it anymore."
In horror, women who take bloody and excessive retaliation are common, and it can be a feminist (or just plain enjoyable) experience to watch. These films may not be moral, but as Lady Gaga said when asked about her character Patrizia Gucci, who hired a hitman to murder her ex-husband in House of Gucci (2021), "I don't believe in the glorification of murder. I do believe in the empowerment of women." "