Why did groups like the red shirts participate in violence in the months prior to the gubernatorial election of 1876?

The Hamburg Massacre (or Hamburg Riot) was a key event in South Carolina during July 1876, leading up to the last election season of the Reconstruction era. It was the first of a series of civil disturbances, many of which Democrats planned in the majority-black/Republican Edgefield District, to disrupt Republican meetings and suppress black voting through actual and threatened violence.[1]

Beginning with a dispute nominally over free passage on a public road, this incident was based on racial and political grounds. A court hearing attracted armed white militia numbering more than one hundred, including members of Red Shirts paramilitary groups.