By extension, one owns any product of one's life. Be it an idea, materials harvested through our own efforts, refining of such a material or assembly of components to make a whole. This is all good. At any stage in the process, value is added.
The root problem is what we call "commerce".
Let's say that there is a small farming town. One person grows wheat and sells it to another who mills the wheat who in turn sells it to a baker who in turn sells the bread to everyone.
Now, if someone with a lot of money came to town and decided to buy all the wheat and just hold on to it. Eventually, the second person will have nothing left to mill. The baker will have no flour with which to make bread. Everyone runs out of food. Starving, they BEG the man who bought all the wheat to sell it back to them. He agrees, but the price is much higher than it ever was. He takes their money and goes off to the next town.