People automatically attribute virtue and goodness to the idea of sanity. The more sane someone is, the more rational and, therefore, the better decisions they will make.

But what if a higher level of "sanity" leads to actions that are ultimately bad for those who are less sane? They could perceive the world exactly how it is and conclude that destroying that world is the best course of action. How does one differentiates this behavior from actual insanity? It makes sense that one could tell whether someone isn't sane, since someone who is insane probably wouldn't have an experience consistent with other people, but hypersane bad guy seems difficult to accurately assess; they might be sane overall, but be totally insane in one particular facet, or perhaps not at all.