Where are you getting this "War Criminal" stuff? I don't see how any of the things that his forces were said to have done constitutes a "war crime."
I've seen video of captured combatants being summarily executed by an American firing squad in the Philippine insurrection. That is how things were done in those day.
It’s been understood that murdering prisoners of war is not to be done for centuries. We know that people have played loose with the concept, but the American military has always taken a dim view on POW killing.
General Pershing did not do this.