Both Jeff Davis and R.E.Lee were men of letters who opened their hearts to both wives and children all thru their lives. If one truly wants to get a grip on the Southern view and thinking that went into the whys and wherefores of this conflict there is no better place to understand and also separate truth from fiction.
Lincoln while not a man of letters was a speech maker who grew into a ok type honing his skill before the bench and in public yet he was a private and timid man with few real friends so his letter writing is both shallow and limited. Political speeches give little if any real feel into a person's heart because they are saying things they think you want to hear. Where we get a different view of Lincoln is in his private meetings and notes and he is a very different person there imvho.
There is a deluge of letters (1000's if I may say) from both Davis and Lee. In fact it seems that letter writing in the South of that period by many of the leaders gives us a fountain of history to both draw from and judge the true reasons for the war apart from all the politico blustering and fanatical screaming that one gets from speaches.
The same is true if you want to judge the hearts of both Sherman and Grant. Read their letters to their wives, I rest my case!