“So if the Union foragers had only given out worthless scrip based on a valueless currency, it all would have been okay?”
That would have been a start at civilized behavior. Then if union forces could have restrained themsevles from burning the farm while carrying off any valuables might have sealed the deal that the union stood for something other than brute force. I don’t know, but it seems pretty simple. What would be your reaction if today’s servicemen acted this way towards any civilian population it occupied? Just askin.
The United States wasn’t much interested in “sealing the deal that the union stood for something other than brute force.” They were trying to end a war that had dragged on for four years by destroying the enemies will and ability to fight. The rebelling states could have stopped it any time they wanted.
Hell, the rules of engagement for the USA and Marines in Taliban occupied Afghanistan are more civil than Sherman's Marching Torching orders.