Really? What's your source for that? What would rain do to cotton bales out in the open?
Why would Hampton give orders not to fire the cotton unless he put it there for kindling?
That is what Sherman's Torches were doing, burning everything.
You've given no evidence for that, whatsoever.
As Sherman later said, if he had intended to burn Columbia, he would have done a complete job if it without concealment.
You are ignorant. They have books on the subject, the torching of the south, well documented.