Why did the author’s mom get so angry when he hit his sister when he was three years old in The Other Wes Moore?

In part 1, chapter 1, the author describes an incident in which his mother disciplined him for hitting his sister, Nikki, who is seven years older than he is.
To his surprise, the author’s mother, Joy, yelled at him to go to his room because she had told him not to “ever put [his] hands on a woman.” His father understood this was an inappropriate reaction for the three-year-old, but the author remarks that he would later understand why his mother became so enraged at his behavior.
Joy was married to Nikki’s father, Bill, before she met Wes’s father. Bill was a drug addict who struggled to adapt to adult, married life after college. When Nikki was just one year old, Bill and Joy had a violent confrontation during which he physically assaulted Joy after yelling at her to do the dishes.
Joy’s history in an abusive, toxic marriage influenced her emotional response to seeing her young son punch Nikki.