I am surprised, no one willing to discuss the concept of property? 

Property is part of  a system to share limited resources, calling it theft is almost self-contradictory. How can someone steal something if owning it isn't allowed in the first place?

The basis of property and governments for that matter is force. There is no fundamental reason that one person should control property and another should not. My ancestors killed a bunch of people and circumstance has left me in control of this property is hardly convincing.

The next argument - that you worked and earning money and exchanged it for the property also suffers from the same flaw, at some point, somewhere force was used. Current owners and controllers of property are not based on free exchange, but on significant power influences.

The order and time of your birth does not give you innate rights to property.

It's power first and justification after the fact.

We are talking in fundamentals here, right? The problem with the term "theft" is that it is associated with right and wrong. Title to real estate is not theft in itself. Title may be questionable though. The authority to confer title is a matter of social organisation. If our allegiance is given to the title creating authority calling property theft is contradictory. Territory is held by force. Like Pi in the lifeboat. He was not stealing from the animals. He was organising things in a way he thought was better, and benefited him. The rights and wrongs are different subjects.