it's an ideal, not a metaphysical necessity. But we need to enforce the ideal because otherwise the powerful use their power to their interest and against their detractors. It is absolutely essential to hold them responsible for their decision making process if we value life in a liberal democracy or a classical republic. They cannot get every decision right, but they must at least get them wrong for a fair reason.

Otherwise it's just "personal responsibility for the many, riches and fiefdoms for the few"