Of course, the problem with listening to the voice of the people is that the people might err. Mosiah exhorts his people to choose in accordance with Yahweh’s commandments; in so doing, they will always find themselves in the right. Consequences of a wrong choice will be visited upon their heads—a just punishment because they will have made the decision.
Shifting the responsibility from the king to the people might make people long for a king and, hence, for lessened responsibility. Mosiah reminds them that having a king does not insulate them from Yahweh’s wrath. They can still suffer even though it will be because of an evil king, not necessarily because of their own choices. Mosiah is showing them a contrast. While it is true that rights engender responsibility, having a king bear that responsibility instead of them personally will not protect them from the evils of the world if the king is not righteous.