Why do governments have stricter rules about decision-making than private organizations do?

Open ended

Governments are supposed to have limited power because they are meant to serve the people, not the other way around.

Considering that, having stricter rules mean that the rules won't jut "do what they want" when in power.

Having strict rules and strict functions to each statesmen means that they are more likely to do what they are meant to instead of turning the power of the government against the people.