There's a large body of literature that attempts to justify centralization of power. Social contract theory, to name one. You may not agree with it, but the possibility of a justifiable centralization of power can at least be argued.
Of course there is. We've lived under centralized power for hundreds or thousands of years, after all. Why would The Powers That Be suddenly cease wanting to Be?
But centralized power cannot be justified, it can only be rationalized. If you think about the idea of the social contract for a moment, you should realize that it's not a contract at all, but merely a shackle for our minds, to keep us from finding a way out of the maze of our brainwashing.
For starters, you were never even asked, you never had a chance not to participate, and you can't just opt out of the system either. You're either inside a country, or you're freezing to death in Antarctica. It's not much of a choice, but a voluntary choice is necessary for any contract to be binding.
Read this: http://spot.colorado.edu/~huemer/book3.htm
Another difference is that the "system of property" actually works to everyone's favour - quite the opposite of "the social contract", and imposes no other obligations on you than to not aggress against anyone else's property. If "aggress" sounds out of place, let's say "interfere with someone's (exclusive) control of their property". There's lots of room for pointless bickering in moral issues, etc.
There are various sensible ways to view the concept of property. One is Murray Rothbard's idea of something becoming your property by "mixing your labour" with it. For example, if you build a house, or plow a corn field, they're your property.
Well no. If we're talking about capitalist property, it's between a single individual and the entire rest of the human race at once. Or, if we want to be realistic, it's between an individual and anyone in shooting distance of that individual.
>Another difference is that the "system of property" actually works to everyone's favour
No, it works to the favor of property owners and creditors (who are, essentially, fractional property-owners in people).
>imposes no other obligations on you than to not aggress against anyone else's property
Since the entire world is thus privatized, this "one simple trick!" becomes totalitarian.