Yanks will come up with post-facto psychological arguments to justify the North’s hypocrisies of keeping slavery in the North through the war, using blacks explicitly as cannon fodder, and leaving their communities destitute which led to the starvation death of over 1,000,000 “freedmen” they claimed to save — the truth is the facts simply aren’t there to make their moral case.
You’d have to make up an ex-parte narrative, cherry pick speeches, blatantly ignore actions, and justify the greatest hypocrisies of American history to come to the conclusion that the North was moral and correct.