It's a revenge exploitation movie, a revisionistic fantasy. (And how many blaxploitation movies from back in the day would that first sentence apply to?)
It's QT remaking junk movies of his youth. Just with bigger budgets and better casts, and usually better than most of them.
I mean he's done his kung fu/martial arts girl power movie (KILL BILL), Jews (INGLORIOUS BASTERDS), and now African-Ameriacans (DU.)
I do find Lee and QT still continuing their feud since QT was in one of Spike's movies. I believe it was GIRL 6.