This is a bit late but I absolutely do not understand what you just said, buring down a city and giving explicit orders to kill everyone and let no survivors including women and children is not morally justified, Dalinar was betrayed by the people he's trying to conquer he was the aggressor.
I also don't understand how you draw the line at Adolin killing the man that's that has killed many of his own friends and comrades, literal thousands of his people were killed from Sadeas's betrayal and he's both continued and threatened to do more.