During the Gettysburg Campaign, Barksdale was in something of a snit.
During the Chancellorsville battle, the Mississippians held part of the "stone wall' at Fredericsburg. A MS colonel had allowed an informal truce to Federals to retrieve their wounded. Federal officers used the truce to examine troop placements. A while later, a mass bayonet attack at the perceived weak point forced the Rebs out of Fredericksburg. That incident may have been on Lee's mind at Cold Harbor, and influenced his refusal to allow informal truces.
Barksdale became incensed when details of that action were made public. He resented any black mark on Mississippi and made his own accusations. And he seems to have become something of a "berserker", bent on pretty much what he did at Gettysburg, which was go and not stop.