"I'm on your side, but I do think it's a leap to think the white people of the North were so altruistic back then they would fight a 4-year war to free slaves. Maybe it was a basket of issues?"

That is absolutely true. The same can be said for Abraham Lincoln. His goal, as well as many other Americans above and below the Mason-Dixon line was primarily to preserve the union and to continue to benefit from the abundant agrarian and productive economy of the south.