I disagree, you had no actual right to create the property in the first place. It's like trespassing and the actual owner grabbing a dumpster and cleaning out your stuff.

Literally the user has no rights in that case.

Property rights including intellectual property rights don't attach to the tools used to create them. This is why your drawings aren't copyright bic and bram moolenaar isn't a billionaire.

What property rights do attach do is clearly peoples physical property with precedent going back thousands of years before we dreamed of copyright. By extension the files on said property ought to be secure against vandalism courtesy of more recent rules.

Believing that a running application on another persons computer transforms their physical property into your property requires magical thinking. The IP right is an orthogonal issue that has no bearing on their right to their own machine and their own files.

Its as if you stole my pen and went on to write a manuscript and I broke into your house and burned it.

Both acts are orthogonal and the ethics don't intersect in the wholly magical way you imagine. I would owe you one pen or the money to buy one and I would owe you for your manuscript plus owe the country for the crime of breaking and entry or in this case inappropriate access to a computer.