In reality, however, the government of the United States is a force seperate from and placed above the people. To say that any government is controlled by the governed is a strange proclamation: the entire function of government is to place some people in the position to coerce the citizens through a monopoly on the use of violence. The only want the control of law can be maintaned is violence and the threat of violence. Cops derive authority from the implied threat of force to those who disobey.

On a level more specific to the United States government in particular: the U.S. system of government is based on a concept of "consent to be governed". The votes that elect public officials are taken as the implied consent of the populace to be governed by them. However, the majority of the population does not vote in national elections, and as such do not imply their consent to be governed by those who are elected. Even within the framework that it has set up for itself, the U.S. system of government is illegitimate.

Since government is not an institution to excersise the control of the people, and is in fact an institution set up to excersise control over the people, it follows that public property is not "public" at all. The word "public" implies that it belongs to everyone. In reality, it belongs to the state, and one requires permission from the state to use that which they say belongs to "everyone". If by "everyone" they mean "government beauracrats", then this is an entirely accurate statement to make. If not, it is misleading, to say the least.
In my personal experience, I have seen police punish the use of public space for unauthorized activities ranging from playing music (only a crime in a truly pathological society), to giving away free bread and salad to homeless people on the street corner, to drawing art on sidewalks with wash-away chalk (art that was totally unobectionable in content, I might add).
Thus, public property matches the hierarchical and authoritarian nature of private property. Where private property places the power of economic resources into the hands of a class of rich business men, public property places its resources in the hands of government officials and the lesser-beauracrats employed by them.
The key aspect of both private and public property, and the way in which they combine to create an overall system of control, is that control of space is always given to people other than the ones that have to use it. The workplaces aren't left to the people who work there. The streets aren't left to the people live and walk them, but are given to city commisioners living in upscale high-rises. Housing isn't given to the people that sleep in it, but instead given to parasitic landlords.
To put it simply: lives aren't given to the people who have to live them.