I would suggest that blacks and everyone else re-read world history and remember all the cultures and people who were made slaves and were slaughtered throughout time. One can start with the Jewish people. As I recall, throughout time, armies conquered lands and made slaves of the people they conquered. Considering world history, one would think that all of us could stay enraged all the time over past history. As a Jew, the Holocaust comes to mind.
I suggest everyone re-read US History. Every time I hear some pundit talking about segregation and whites only drinking fountains I am reminded of my father. He was born in 1923, graduated from high school, and never attended a segregated school. He also never encountered a whites only water fountain. People like to look at race relations in the south and assign that behavior to every state. It just was not that way everywhere.