There are the obvious reasons it's wrong, and then... There is the overlooked reason. Besides that, it's contrary to a No Kings ethic, not to mention the Zero Aggression Principle and Human Respect. Maybe, when you believe the ruler's heart is rotten and his actions stink, instead of violence, there's a role for a higher power. With that, there's an action that promotes peace in the heart and only then... Peace in the land.