It's kinda disheartening seeing the amount of people in this discussion who either haven't been paying attention to the story or can't empathize with the rebels regardless.
The continent was in a 70 year long state of peace until Cheong showed up. The only reason the war happened was because Lohen's followers manipulated events behind the scenes to get Opher to view Cheong as being worth his time. If Cheong hadn't showed up, peace would have lasted an unknowable amount of time before either Opher got tired of waiting and killed everyone, or someone else showed up to interest him.
That said, the grannies seem to have kept it mostly to themselves that the only reason they weren't exterminated 70 years before because Opher was bored, so the common folk likely wouldn't know either how hopeless the situation was, or that Opher eventually getting tired and wiping them out was inevitable. From their perspective, everything was fine and there was peace until Cheong showed up, and their families died as a result. She beat the big bad who she inadvertently got going in the first place, but their families are still dead, and what's to say she doesn't inadvertently get some other pyscho going again.
It isn't so much illogical as it is entirely unfair to Cheong by not accounting for intent, and presumptuous in assuming that it could happen again.