A lament it was, but we shouldn’t ignore the faulty logic because of the genuine emotion behind it. Because speeches like that are intended to create new emotions wand though it didn’t name much if a difference then its importance for our collective historical understanding is difficult to underestimate. Though the average citizen will be hard pressed to delineate the causes leafing up to the war—besides a flat assertion of “slavery”—nor how the war was fought, nor what came after, they can probably quote a few words at least from the Address. Those people might be tricked into believing representative democratic republicanism, or whatever you call our system of government, was in danger. Which is a lie.
Fault some hyperbole, but Lincoln was saying “Look at it shrink, unless we stop that.” And to tell the truth, most of the reconquered areas, SANS slavery now for 150 years, are the greatest boon to that ideal today!