An offline reader of this, before it was published, said I should have included the common saying, "If you aren't better than a ..., what are you better than?" I think that's the answer. Po white folks have been treated so badly that, historically, they have lashed out at the only people who have been treated worse, whom they can get away with denigrating and committing violence against.
Thanks for commenting, and for asking this particular question, John. Your question and my answer my generate some discussion.