Moral relativism: that's how they're able to massage it out of their minds. They don't have universalizable moral and ethical principles whereby murder, cannibalism, footbinding, sattee, slavery, whaling, headhunting, genocide, etc, is wrong no matter who's practicing it. These people use the "their culture, their standards" justification for every unsavory thing they wish to overlook in their attempt to whore themselves out to those who impress them.