I don't think I've ever said it was completely justified....but It certainly was justified to some extent, unless one thinks people should be allowed to murder/rob/ destroy homes to run out innocent people without any punishment at all, I certainly don't. One big difference every historian notes that you seem blind to, is Lawrence was in a fact a nest of thieves and murderers and the raid there was to pay them back for the misdeeds they had conducted..... Guerrillas had list of guilty to go after. Historians note there were warehouses in Lawrence full of stolen goods.
Jayhawkers raids weren't, they were random, not targeting anyone for anything, just to conduct wholesale robbery for personal gain, they would just cut swaths through countryside's robbing and burning all. And whole towns for example's Osceola, Dayton, Papinsville, Butler, West Point, Rose Hill, Columbus, Chapel Hill, Holden, and Morristown. Between the two think any serious historian could answer between the two which was motivated primarily by monetary gain, every one I have talked to at roundtables has, and its the jayhawkers, notable difference in motivation. Revenge may not be pretty, but more noble then just petty greed IMO.