Laws of physics don't exist either. What we have are our descriptions of the organized ways in which things seem to work based on our observation and experiment. But a hard coded rule doesn't exist anywhere, which is why we adjust our laws sometimes when we find new behavior through different or better measurements.

To get to your point, laws and rights are agreements within a society that things should be a certain way, and can be changed by the public or those who govern them, positively or negatively. As George Carlin said, you don't have rights, you have privileges. And those can be taken away, even the ones claimed as given by a creator. That's just core agreements, and even they aren't perfectly adhered to, especially if most people aren't paying attention.