Open Source Supporter = Copyright Supporter?

gbulmash writes: "This essay claims that without copyright granting an author the right to set licensing terms for his/her work, the GPL could not be enforced. It says that those who support the GPL while calling for the abolishment of copyright are being unintentionally ironic, because they're calling for the abolishment of the exact thing that makes possible the alternative they're supporting. It concludes that if you support the GPL or any open source license (other than public domain), your argument is not whether to abolish copyright, but how to reform copyright."