Because if it doesn’t, Harmony won’t step in. The system had been quite clear about that, in its historical behavior if nothing else. The system did not care what atrocities those living on the surface wrought on each other, so long as they did not attempt to damage the ring itself or any of its systems. Othar could go to war with Equestria, destroying both in the process, and Harmony would act no differently than if they were having a minor argument over the outcome of a game.