Theft is something that is frowned on in most societies. People have their property and like to put a barrier around it so that they keep it for their personal use. Of course, some people allow or encourage things to be shared but that is their choice. They would be upset if someone broke a window and took the things that they had shared with others.
Some of the things that we can take away from others that leaves them upset are things that are not as easy to quantify such as peace and quiet. Another thing that is not always easy to define is intellectual property. Intellectual property comprises of ideas that can be expressed in images or in words or as inventions and includes things like copyright, patents and trade marks.
In all the examples given there are laws that set up barriers to prevent people from losing the things that they want to keep. There are also things that you can do to help protect your property.
The obvious things are fitting locks and using other ways of making it hard for people to steal your property. It is also why some people add watermarks to images or add passwords or other similar devices to documents that are emailed or downloaded.
There are good reasons for these barriers so they need to be respected.