In general, I'm getting the impression from your comment that you have some overly idealistic beliefs, and that you're perhaps unwilling to engage honestly with ideas that are counter to your own, but in any case..
Re: The Dawn of Everything
You're saying you don't agree with him because of a book you read - but that book has legitimate historians making some pretty bold criticisms: "cherry-picked and selectively presented examples", "perilously close to scholarly malpractice."
There is some positive feedback as well, but in general, if a book claiming to be historical elicits this kind polarization, it's probably not something to base a strong belief on.
I'm also not quite sure why you would find it hard to agree with the notion that, throughout history, humans have been protective of their territory. The list of examples you could point to for this is unending.
> Why then some people usurp land and natural resources and not let others use them?
You're question here doesn't really do accomplish anything re: property somehow being theft. I would suggest that "the reason" some people aquire land and don't let others use it can simply be because they don't want to. Sometimes the answer is that it's not financially viable to share it. Sometimes the answer is that they fear the destruction of the land or resource if they just open it up to anyone. Any of these reasons is sufficient, because they don't actually need a reason.
> If you agree that there is no natural rights, then how do you justify private property rights?
To start, the other guy never claimed private property was a natural right. The rights we have emerged from people wanting to self organize for their mutual benefit. They needed to agree on some fundamental protections that enable an actual net benefit of their organized society, and giving people rights to own and protect their property is generally needed for people to feel confident that effort they put in to improve the land is effort they will be rewarded for. It's a nice idea that people will improve land for the good of humanity, but in reality, people are not motivated by that enough to overcome the people who would abuse that system by "free-loading". It should tell you something that private property + property rights have consistently emerged, whenever people have tried to put together a society.
> Please share your sources for this statement
I admittedly didn't know much about this, but on some cursory research, it seems pretty obvious to me that this was not an entirely "free choice" based movement..
"Rebels wore ski masks and used furniture and other office materials to barricade themselves inside of buildings once they had taken them over.[11] During the occupation of the city, rebels also painted pro-Zapatista statements on the walls of buildings.[12] While raiding San Cristóbal de las Casas, the Zapatistas released 230 predominantly Indigenous prisoners from jail and also demolished land records in protest"
And the source you're asking for: https://en.wikipedia.org/wiki/Zapatista_uprising#Events