One should always remember that the not so nice practice of slavery was a Jewish, Christian, Islamic and Pagan tradition. However it was one particular branch of Christianity that saw this mean way of life go the way of the Dodo, at least in the West. Of course, things are not perfect but they are much better.
Here is an imaginary flag of Northwest Europe. The Basque, Brittany, and Catalan are peoples yet are not independent nations. Their flags can cause quite a stir among certain peoples in Europe. Likewise the old South Africa flag does the same as well for many in Africa.
The South Africa flag is the basis of this educational type of flag. Its purpose is to provoke a response on the identity and relativity. Depending upon ones frame of reference it can cause quite an emotional response.