But mostly, I think it's just that we have a forum for Civil War discussion here. Most people in America probably aren't thinking about what happened 150 years ago all the time. Outside of specific Civil War forums, every four years you get somebody or other saying the country should split up again. It's tied to the elections, and it always gets an audience with the losing side. It can be cynical as well, since it's a good way for a disgraced journalist or aspiring blogger to get hits on the Internet.
Most people in America aren't thinking. Period. The elections of 2008 and 2012 clearly demonstrate that.
The northern and southern sections of the country are almost like two different cultures and have been since colonial days. Secession was bound to occur at some point regardless of the occasion and may possibly occur again.
350 million people ruled by 535 that try to shoehorn the entire population into politically correct federally run programs/services/etc is wasteful, ineffective and destructive to life, liberty and the pursuit of happiness.