The point I was attempting to make is that once the shooting started, the reason for secession became irrelevant. War feeds upon itself and drowns out everything else. A favorite saying in Vietnam, "When you're up to your a** in alligators, you forget that your job was to drain the swamp."
When the Civil War started, a whole new dynamic took charge. Men had to fight to defend their home states. It doesn't matter that their homes needed defending because of secession. All that matters is that there's a war going on, and men have to do their duty. Eloquent political speeches and appeals to right and wrong are lost in the roar of muskets and cannons. You fight to win, and leave it to history to determine whether the cause was right or wrong. Soldiers don't have that luxury.