I'll strongly disagree with you on this one. No doubt there were just as many 'good people' fighting for the South as there were for the North, but the cause they were fighting for was morally repugnant and evil.
While we're talking war, I'm guessing there were a lot of 'good people' fighting for Nazi Germany during WWII too.
What I'm saying is that it was more a level of bad. The North was fighting for the right things but not necessarily because of "nobility".
We certainly didn't enter WW2 because we wanted to end the holocaust. We did because we didn't want germany to take over the world and control us. There's nothing wrong with that, but we need to be careful in painting ourselves as heroes.