Okay, but why is America as diverse as it is with black people? It's not like there are a lot of black people because they immigrated... it's because white people on boats kidnapped them, brought them to america and kept them as slaves. Most of the black people you see in America have similar stories from grandparents and great grandparents.
So kidnapped, brought to America as slaves, then kept in chains for a few generations and then freed. Once freed, they were still discriminated against until recently. That's a shit ton of bad history right there. Explains quite well why they're upset and why they are in the position they are in and why racism still exists.