Or perhaps the propensity for Federal troops to bombard civilians?
Consider US General Gillmore's demand of the Confederates. In August 1863, he demanded "immediate evacuation of Morris Island and Fort Sumter by the Confederate forces" or else he would fire upon the city of Charleston "from batteries already established within easy and effective range of the heart of the city."
The Confederates didn't surrender the forts, and the Union army bombarded civilians in Charleston for the next 18 months.
Charleston was reaping what Jeff Davis sowed about 2 1/2 years before.