Humans are pack animals by nature, and thus have the natural instincts to protect their pack. Males are naturally the dominant ones tasked with protecting his mate and any possible children. Females are attracted to a strong man who is able to protect her.
When another person attacks any family member or someone close to someone, the urge to defend them takes over. This is also highly true when someone attacks a man’s wife. We know that love makes people do crazy things, and things get uncertain when anger comes into play. Strong emotions will override logic every time. You would expect something similar when it occurs to a person’s mother, who raised them since they were a baby.