I'm one of the people that uses the GPL because copyright exists. Without copyright, companies lose the incentive to close their source, because the binaries aren't restrictable anyway so they can't profit off that. It just means they shoot themselves in the foot by not showing the source to others for auditing purposes. It would also mean decompiling binaries would be perfectly legal, and distributing the results of that would be legal too.
I'd rather live in a world where nobody can tell you how to distribute information than one where I can try (and personally wouldn't be able to fight jack in court enforcing it without the FSF's help) to force openness on others for the sake of freedom while international companies profiteer off artificial scarcity.