So this summary I'm going to give really does not do justice to the whole situation, but I'm going to try to be brief-yet-informative:

In 1921, Tulsa, Oklahoma, a black teenager, Dick Rowland, was arrested for 'assaulting' a white woman (most reports say he likely just tripped and accidentally touched her as he fell; she declined to give a statement). At the time, the black community in Tulsa was one of the most financially successful in the country, colloquially called "Black Wall Street." Meanwhile, the KKK and racism in general were at a historic high across the entire country, not just the South. As news spread over the arrest, a large group of white people (some of whom had been deputized earlier that day for this exact purpose) arrived at the jail to lynch Rowland as well as a smaller group of black people who arrived to defend him from what was certainly going to be his death. Some sources disagree on how EXACTLY the violence started but the general consensus is that the police convinced the black group to go home but someone in the white mob tried to disarm them before they left, possibly even trying to wrestle away someone's gun. A shot was fired, and then many, many shots. Over the next 16(ish) hours, white mob violence burned down 35 square blocks of Black Wall Street (at least 1250 homes), somewhere between 50-300 people died, many hundreds more were injured, and not a single criminal charge was brought to anyone. Also insurance companies refused to compensate the black families because obviously

Fast forward to 1996, and the city of Tulsa formed a committee to investigate the Massacre (only 75 years late). The committee found that the city was at least partially responsible and should (among other things) pay reparations to the few remaining geriatric survivors who would have been mere children at the time. The city refused to do follow their advice (even though they were the ones who MADE the committee in the first place) so a lawsuit was attempted. It was thrown out because the statute of limitations (which was only 2 years for a civil rights claim) had long since passed. Although the city DID give out some medals to the survivors as if they were fucking Olympic athletes or something and not the victims of a state-supported hate crime/murder spree

It's another example in a very, VERY long list of American hypocrisy, broken promises, and racism that we refuse to even acknowledge on an official level. It's kinda similar to modern-day Japan denying that they committed any war crimes during World War 2 despite the mountains of evidence to the contrary