willing to rape other men to dominate them certainly aren't rare. Look at the prison rape problem. That problem isn't caused by 'women dressing like sluts.'
As far as the African women who leave their raped husbands, that certainly is no way to support a hurt family member, but those women have been told every day of their lives that they had to have a man around to protect them (and in Africa, I would think this is truer than for, say, the U.S.), and once the man has proven that he can't protect himself, what is she to think? She herself has been denigrated all her life as weak, a 'wife,' in need of protection, in need of a man's strength, and all of a sudden.....she has no protection. And she has herself and a child to protect. Well, my take on this is that men of a patriarchal culture who portray themselves as leaders and protectors and women as weak and stupid and in need of a man, any man, should not be surprised when he is discarded when he cannot provide what he said he would. Let's begin with that. Patriarchy hurts everyone, folks.
The sort of lawlessness that allows brutal men to brutalize other men indiscriminately is the same lawlessness that allows child soldiers, kidnapped 8-year-old girls made into 'wives,' wholesale rape of any woman caught out somewhere by herself, brutal poaching for cash, etc. It is the result of a lack of laws, lack of enforcement, and the presence of total corruption. If the U.S. is not careful, we'll be seeing it here, too.