I just came across the below, and it struck me as relevant to the recent demands from extremists to label local businesses as "Black" or "White" and only shop at "Black" businesses.

"In 1933, as the starvation in the USSR reached its height, the Nazi Party came to power in Germany. In the euphoria of victory, Nazis tried to organize a boycott of Jewish shops. This was not very successful at first. But the practice of marking one firm as "Jewish" and another as "Aryan" with paint on the windows or walls did affect the way Germans thought about house-hold economics. A shop marked "Jewish" had no future. It became an object of covetous plans. As property was marked as ethnic, envy transformed ethics. If shops could be "Jewish," what about other companies and properties? The wish that Jews might disappear, perhaps suppressed at first, rose as it was leavened by greed. Thus the Germans who marked shops as "Jewish" participated in the process by which Jews really did disappear – as did ...