Copyright is but one pillar of intellectual property law.

I’d like to see an attempt by useful freedom respecting software projects to deploy patents to combat non-free reimplementations.

A GPL license that grants you rights to the backing patent as long as the software you develop with it is also released under the GPL license.

Use the library for closed source software? Copyright violation. Reimplement the software under another license? Patent violation. Create something slightly different and call it the same thing? Trademark violation.