Nonsense. The capacities of an organized group of people are very different from the capacities of any individual in it or the averaged capacities of its members. Even an absolute dictatorship where the dictator is resident genius.
Your claim is only correct if it's a dictator with an army of automatons. The claim you want to refute is just as wrong, unless the people follow a strict algorithmic decision procedure, which even the stodgiest bureaucracy only loosely approximates.
Agents and groups have fundamentally different dynamics. An anthill does things no ant can conceive of. Many human organizations filled with smart, well-intentioned people do incredibly stupid things. Etc.