The Confederacy little understood or cared about the mismatch with the Union regarding warfighting.
They thought they could strike first and hard and sue for peace.
The Union fought to win, ruthlessly, that’s war for ya. If ya don’t like it, don’t start it.
Of course Sherman was a drunken, lunatic, killer.... And perfect for the job.
There were many atrocities and war crimes committed by the Confederacy:
Silas Gordon, Champ Ferguson, Confederate General John Bell Hood’s burning of much of Atlanta before Sherman got there, Lt. Col. James Keith, “Bloody Bill” Anderson, Fort Pillow, Captain William Clarke Quantrill, Camp Sumter in Andersonville, GA.....
There were far more committed by the union as one would expect of an invader. In any event, Lincoln started the war, not the Confederates. He is the one who sent a heavily armed flotilla into confederate territory.