DJ, it was ALL about money. They were taxing the hell out of us. Lincoln, himself was on record as saying, "I don't care what they do with their darkies, so long as they pay their taxes". Another gem was, "If I could save the union by freeing every slave, I'd do it. If I could save the union without freeing any slave, I'd do it.". Wow, doesn't sound like the great emancipator really gave a rat's ass about the slaves, did it? As for those taxes, and that money, you apparently haven't studied up on the true founding of this country. It was NEVER supposed to be about bleeding the states to grow the federal government. It was ALWAYS supposed to be a union of strong states and a federal government with very limited power. There's a reason our forefathers only gave the fed two important jobs, to provide for the common defense, and to regulate interstate commerce. They stole money from the south to make purchases to expand the "empire".
As for Ft. Sumpter, they were given ample time to vacate. It was SC property leased to the federal government. Upon secession, that lease was null and void. They didn't leave. They chose their destiny.