It is important to contextualize these. What Sherman did was, under no circumstance, good or justifiable, but it should also be noted that Sherman's destruction of the countryside did actually have military goals in mind, and further was not the disorderly mass violence that the Lost Cause Myth has so frequently tried to paint it as. Sherman's targeting was, by and large, very specific and was far from what we would describe today as total war or indiscriminate combat.

There were a few exceptions, but there is not any record of mass sexual violence, murder, etc. The campaign was targeted, resulting in the destruction of infrastructure like railroad lines, bridges, telegraph infrastructure, etc. And what Sherman did was really not any more alien than what had already been happening, with the only caveat being that much of it was of Sherman's own planning because he was deep in the South and operating without regular communication from superiors.

This also did have immense effects on ending the war sooner. In fact, it demoralized the South so much that at some battlegrounds the Confederates had to put picket guards at their own rear to prevent mass desertion of troops. Sherman's work was instrumental in damaging the Georgia war effort and the Confederacy's morale in general, and as a result we can definitely say that his March to the Sea was a great benefit in helping to end the war.

As for the misery and such, well, the only people to blame for that were the Confederacy. The Civil War began as an act of Confederate aggression to protect the institution of slavery, which all of their leadership and their State Constitutions and declarations of secession all declared was the leading cause of the Civil War. They inaugurated their own president before Lincoln was even inaugurated, then began numerous violent acts to seize weapons and destabilize federal reserves before Lincoln was even sworn in. The Confederacy's economic turmoil from the war was a devil of their own making, so to speak, and all for the protection of the institution of slavery, which the average Confederate soldier knowingly worked to defend, as I've discussed here. Had they not been so eager to protect the slave trade, and then initiated the conflicts that led to the Civil War, then they would not have been devastated, given that the Republican North wanted to desperately avoid a war if possible.

But let me say again, the violence that Sherman did was terrible and we should not seek to say it was good or justify it. It was harmful, it was horrible, and it did leave a lasting and damaging affect on endless families and homes throughout the South. But it was necessary, it did hasten an end to the war, and it was by no means something that (even in today's world) would garner him a title of a war criminal. The United States did similar (in fact even MORE devastating and horrific acts) during WWII in their invasion of the Japanese controlled Islands, during their hopping campaigns, and also in Germany. A war criminal he was not. But he was brutal, and we should not look up to him as some kind of hero. But if the South didn't want to feel the results of war, they should not have started a war to begin with.

Much of your ideas seem to be based largely in Lost Cause myth rather than history of the war itself. For a few good books on this, I suggest reading:

Charles Royster, The Destructive War: William Tecumseh Sherman, Stonewall Jackson, and the Americans (Vintage Civil War Library, 1991)

John Majewski, Modernizing a Slave Economy: The Economic Vision of the Confederate Nation (U of North Carolina Press, 2009)

Mark Neely, "Was the Civil War a Total War?" Civil War History 37, no. 1 (1991): 5–28