A couple of points:
I averred out that crimes are committed by soldiers in every army - the quality of a commander consists in whether he permits or forbids such crimes to be committed and whether he punishes such forbidden crimes when discovered.
Your posts show that Sherman did not approve of such activity, and that he punished it when discovered.
Also, Fellman's quotations of Poe are interesting - in light of the fact that Poe was tasked with burning down the remainder of Atlanta and that he did it.
I highly doubt that Poe, a trained engineer, was stupid enough to believe that a city that was a core railhead in the center of the South was "of no military significance."
Sherman informed the mayor that when he surrendered the city, the bombardment would end - and the mayor surrendered and the bombardment ended.
Finally, your list of towns that were partially burned underlines the fact that they were not ordered to be burned. Some fires began as deliberate acts of sabotage by Confederates who - intelligently - wanted to deprive the Union Army of stores. Some fires began accidentally - posting troops who are building literally thousands of campfires is going to start a large quota of fires in residential areas.
And then there are the fires set deliberately on Sherman's orders: Atlanta.
It is important to note that Atlanta had been burned by Hood before Sherman got there. Sherman cut off the railroad routes, and in a fit of temper, Hood set fire to his train which fire spread. The Union soldiers entering the city had as their first task, to put out the fires set by the Confederates.
The destruction of Columbia, South Carolina by Sherman's troops is a prime example of Sherman looking the other way while his troops looted and burned wholesale. For information about what went on in Columbia, I suggest that you start at the following link to post 147 and subsequent posts all the way to post 229.
http://www.freerepublic.com/focus/chat/2559536/posts?page=147#147
Sherman later testified the following about his actions at Columbia (documented in Post 169 of the thread I just linked to):
Q. -- You testified, a little while ago, that it was very likely they [Sherman's own men] might burn Columbia, and you permitted them, or your officers did -- permitted them to go about the town?
A. -- I could have had them stay in the ranks, but I would not have done it, under the circumstances, to save Columbia.
Q. -- Although you knew they were likely to burn Columbia, you would not restrain them to their ranks, even to save it?
A. -- No, Sir. I would not have done such harshness to my soldiers to save the whole town. They were men, and I was not going to treat them like slaves.
Words fail me.
Once Sherman's troops got to North Carolina, the order apparently went out to reduce the amount of burning and looting, orders Sherman could have issued at Columbia.