Then why did they give the country to the people, then? Why did they make it democratic when they had the golden opportunity to create a monarchy or some other form of totalitarianism.

It would be a stretch to say they gave it to the people. They 'gave' it to their own class of people. White, male, land owners and the emergent bourgeoisie/industrialists. Universal suffrage was a _long_ way off, and arguably never fully arrived in the U.S. due to ongoing racial politics.