I have suggested that one of the reasons that the issue of Civil War causation ignites such heated discussions in some quarters is because people take it personally. At least some descendants of Confederates do not like to hear that secessionists seceded to protect slavery (regardless of what advocates of secession said); all too often you hear that since someone’s ancestors did not own slaves, the war was not about slavery (which confuses the issues of the reasons for secession and the reasons for fighting, and well as muddling the concepts of why nations fight with why people fight).
Another favorite arguing tactic is to argue that since most white northerners held racist prejudices to a greater or lesser degree, neither secession nor the war could have been about slavery. Sometimes you hear that Ulysses S. Grant owned a slave (he did, although he freed the slave prior to the events of 1860-61) or that he owned slaves during the war (he did not) who were not freed until the ratification of the Thirteenth Amendment (factually wrong on several levels, but mistakenly given credence in a piece of sloppy scholarship by the editor of Julia Dent Grant’s memoirs), while Robert E. Lee hated slavery (he did not) and he freed his slaves (Lee was the executor of a will that called upon him to set several slaves freed, and he missed the five-year deadline for doing so). Besides, whether Grant or Lee owned slaves and their connection with slavery is besides the point, because neither one of them played a prominent role in the debates over secession. I’ll deal with some of the usual canards about Grant and Lee later, but it is frankly bizarre that some people need to distort the historical record so badly in support of the illogical argument that says that because the circumstances of Grant and Lee explain why the war came and what it was about.