Yes, they can. The GPL is a software license, that is, it authorizes the use of the software by persons or entities other than the legal copyright holder under

Yes, they can. The GPL is a software license, that is, it authorizes the use of the software by persons or entities other than the legal copyright holder under certain conditions. The legal copyright holder can do anything they want with the software under US law, and any provisions of the GPL that purport to bind the legal copyright holder are not enforceable. I believe Richard Stallman even acknowledges as much.