September 6 is the anniversary of the Atlanta Rebellion (AKA: The Summerville Riot) in 1966. In an event that is quite common in US history, a cop shot an unarmed black man, which was enough to get hundreds of black people to the streets in protest, including members of The Student Nonviolent Coordinating Committee (The SNCC). Police were called in, and fighting ensued.
The white mayor blamed the SNCC for the incident which he dubbed as a riot. He received national praise for his handling of the situation. In response, the black community put together a pamphlet which explained that they weren't out there throwing bricks at cops for entertainment value, but because of real societal problems. Since we're still having these events today... I don't think anyone in power really listened or cared.
Honourable mentions to:
The Charleston Race Riots of 1876. White politicians were seeking to deny black people basic rights again, and guns were brought out.
The Argentina Coup of 1930, which is widely speculated to have been at least partially instigated by US oligarchs.