I'd argue that the lack of scaricity makes owning a work of art less problematic. Someone can always make a new one.

I was born into a world where every peace of land I could use to survive on is owned. But there are an unlimited number of songs or books that can be written. What's the harm in letting a person own the book they created. There are an unlimited number left.

That's not how it works. New ideas are scarce, in that they require effort (and ultimately energy) to create. There are not "an unlimited number left", someone has to actually create them.

However, ideas are not rivalrous. Once they are created, everyone in the world can benefit from them simultaneously at no additional cost. Therefore, the immediate opportunity cost of allowing people to own ideas is far greater than for physical property.