This sounds more like, "Talk Like a Soldier Day".

In "Walker's Division, CSA Greyhounds of the Trans-Mississippi", there is a discussion of the Battle of Miliken's Bend and differing accounts on whether the Texans intended to "take no quarter" or whether they shouted the phrase during the attack. The author summarizes there was no plan to massacre anyone, that dozens of black Union soldiers were taken prisoner and likely returned to slavery. He also states that many of the Texans were poorly clothed, lacked shoes, and he doubts they were inclined to utilize scarce resources to make any black flags. 7.8% of the black soldiers engaged in the battle were killed compared to 62% of the black soldiers garrisoned at the last Ft. Pillow battle. Neither battle culminated in a massacre (MHO).