Wasn't copyleft essentially intended to be "copyright violation as a service"? I.e. making it impossible for an individual working with copyleft code to use copyright to assert control over the code?
Copyleft requires strong copyright protections. Without a license, you have no rights at all to use the code. If you want to use the code, because it's copyrighted, you have abide by the terms of the license.
> Without a license, you have no rights at all to use the code.
Exactly - that is what copyright was set up for (whereas before copyright, people could copy freely), and then copyleft comes and says that everyone can use and modify the code, and the only thing that the license prohibits is the ability of authors of derived works to apply their own copyright. In this way (known as being "viral"), copyleft uses the legal mechanism of copyright to essentially bring things to how they were before copyright.
