Because in this field, to deny one's vulnerability to victimization is to pass from person to authority, to appear and to become separate. We are all colleagues when the issue is coping with human cruelty. Although there are cases of wives who assault husbands, by and large spouse abuse happens because men batter and get away with it. And among humans, the dangerous violators are overwhelmingly male. Males outnumber females as murderers, assaulters, sexual abusers and every other category of violent criminal action.
Males use deadly weapons for sport, for war, for personal gain far more frequently than do females.
The mammalian brain has sex-linked differences associating aggression and male gender. The male hormone, testosterone, is implicated in violent behavior. Laboratory experiments on rats and mice show hormonally induced reversal of gender correlates with reversal of aggressive patterns of behavior. Any attempt to explain why spouse abuse happens must begin with the fact that the male of our species, for many reasons, has aggressive behaviors and these often find expression in the family. Spouse abuse has historic roots.