The bad guys. Confederate member states tend to either be those too unlucky to avoid being conquered in the process of Unification or are outright dictatorships, though they may have thinly veiled gestures towards being a democracy. The "elected" government are puppets, ruled over by the true government, the Confederate Council, which consist of some of the nastiest dictators, black sorcerers, demons, and other unsavory characters there are. The Confederacy in its current form is only the most recent incarnation; it formed and disintegrated many times. It is more cohesive than before, though this is because the Union in turn is more cohesive than its predecessors. If they were to win the war, chances are it would fracture and go to war within itself, prompting some factions within the Confederacy to attempt to make sure that no matter the outcome of battles, the war will never end. At this rate, they might succeed.
It should be noted that there are elements within the Confederacy that often avoid the worse crimes against humanity; some more prominent members, for instance, avoid harming children unnecessarily. However, these gestures do not excuse the atrocities committed against their enemies, nor the suppression of their people, nor the heinous deeds by the more willing of their member states.