There also seems to be some confusion about what constitutes sexism. opebo eloquently but misguidedly points out that many christians engage in Wife Beating. This is a fact. But the identifying feature of the act is not so much sexist as violence. And, even that's not the most relevant point of the act. Nor is sexism probably the underlying motivation here. A man who regularly beats his wife is probably equally capable emotionally of regularly beating his brother. But I'm no psychologist and neither is he, so we both probably speak guesses at this point.
But the point is that society tolerates, or tolerated, the wife-beating, while to varying degrees discouraging the beating of one's fellow man (assuming he was a white of the same class of course, one could beat a black or poor). The sexism was not the beating of the wife, but the toleration of same by the society.