I agree about the use of reasonably civil and scholarly language in our posts. For example, the wiki-article on Jennison describes him as "most brutal and unscrupulous of the Jayhawkers." That may be an understandment, but it does convey the general idea. It should be enough to describe what happened and allow readers to make their own judgements.
If I may respond in behalf of Mr. Allport, the historical postion being debated is that of the Northern "storehouse of virtue." It holds that those who fought for the government served the greater good by saving the Union and ending the evil of slavery. Therefore any misdeeds they may have committed in pursuit of those ends are more than cancelled out. Traditionally many of the Civil War accepted this position, particularly those who view the war from a Northern perspective.
As a result, those with casual familiarity with the Civil War recall the Lawrence "Massacre" but not the "Sacking" of Osceola, Quantrell but not Jennison, Andersonville but not Camp Douglas. Students learn about the laws enacted in Southern states after the war restricting the civil rights of former slaves, but nothing about legal racism in midwestern states. They know about planters who prospered using slave labor, but not about the ship owners and sailors from Providence and Boston who imported them. They associate Georgia plantations with slavery, but have no idea that slaves help to build New York. Other examples are to numerous to mention here.
In other words, the playing field isn't level. A good review of this historiography appears in Edward L. Ayers, What Caused the Civil War: Reflections on the South and Southern History.
[I don't think Danny from Tupelo read the same book that I did.]
I have other questions concerning how violence and repression are supposed to generate respect and loyalty for the government. It seems to work for the mafia; should the same true of a republic? I will hold those for another occasion.