This should explain why she supports it:
> The case arose during the Reconstruction Era from the 1872 Louisiana gubernatorial election which was hotly disputed, and led to both major political parties certifying their slates of local officers. At Colfax, Louisiana, tensions climaxed in the Colfax massacre, in which 105 blacks were killed and three whites. A federal judge ruled that the Republican-majority legislature be seated, but growing social tensions erupted on April 13, 1873, when an armed militia of white Democrats attacked black Republican freedmen, who had gathered at the Grant Parish Courthouse in Colfax, Louisiana, to resist an attempt of Democratic takeover.[2] Over 100 African American freedmen were killed in the massacre, compared to an estimated three whites.
http://en.wikipedia.org/wiki/United_States_v._Cruikshank
And wild guess here — this wasn’t Republicans.