When you commit fraud or print fake dollars, you're interfering with other people's property rights in fairly clear ways. It's an obvious harm. When you sing Happy Birthday to your grandmother, or make a mix tape for your girlfriend, you're creating value through the use of your property. Property rights are especially relevant when you're not affecting others in any way in your own privacy, but copyrights can even interfere with that.

It's not just property rights that copyrights interfere with, of course, there are also other basic fundamental rights being diminished. Freedom of speech is an obvious example.

This isn't an argument against all copyright. It's merely pointing out that there's a tradeoff, and every now and again we should ask "is it worth it?"