It's interesting isn't it? What makes it even more of a coup for the yankees is that some that call on the Confederate cause actually believe it. I just love telling those morons about Judah Benjamin and the fact that the only full Jewish military cemetary outside of Israel is for Confederate soldiers in Richmond, VA
Unfortunately, there's always a Ned Touchstone around to tell these people that Benjamin was "obviously" a mole for the other side.
The Civil War and just whose side one fought on is a very complicated issue. The North was full of copperheads and the South of "tories." My own ancestors were Southern Unionists, which means that my family has been Republican since Lincoln (unlike most Southern Republicans who are converts).
In addition to the slavery issue there was the tariff issue and the issue of fighting against "the Old Flag" (and don't doubt for a minute that that wasn't a powerful pause for thought for many people at the time). Plus, there may be a genuine cultural split. My own upper South ancestors had more in common with New England Puritans than with the strange high church culture of the Deep South. In addition to the slavery issue, the Puritan culture was stark and Calvinistic, being opposed to gambling and alcohol as well as to the alleged loose morals of the slave-holding aristocracy. Although I am now aware that the Bible itself actually permits both slavery and concubinage (not to mention consumption of alcohol!), I still culturally identify with the old 19th Century Republican Evangelical morality. There is still something about Prohibitionism and opposition to state lotteries that touches my puritanical heart.
The men on both sides who died for what they believed in are entitled to respect. No one today should dismiss the Confederate soldiers as proto-Nazis, not should the Union men be derided as "Communists who didn't realize it" (as they are among some neo-Confederates and Southern nationalists).
My history buff hat is off to you, billbears!