Is the main thesis of "The Killer Angels" to show the reader what the soldiers/generals real reasons are for fighting the war? If not what do you think?
I don't think the author's intention was so much to show their reasons for fighting the war, as much as to show the soldiers as individuals. Often, history textbooks dehumanize or impersonalize history, meaning that they show it from such an objective point of view that the experience itself is not made available to be understood by students/readers, etc. The author here gave life to the events and to the individuals involved in it, thus providing us with a more personalized and humanized understanding of a war from which we are otherwise far removed.