It's the branding that allows Red Hat to effectively restrict distribution of binaries, due to trademarks. Since the source is still available, GPL is fulfilled.
My memory of the mechanism was a little different but the trademark component is obviously a part. Something in the EULA like "If you distribute RHEL binaries without our consent, we'll cut off your access to security updates and patches ASAP.".
Regardless, people seem to forget (or perhaps never bothered to learn in the first place?) that the GPL doesn't care to speak to binary distribution, just source code (and -sometimes- build instructions) distribution.
My memory of the mechanism was a little different but the trademark component is obviously a part. Something in the EULA like "If you distribute RHEL binaries without our consent, we'll cut off your access to security updates and patches ASAP.".
Regardless, people seem to forget (or perhaps never bothered to learn in the first place?) that the GPL doesn't care to speak to binary distribution, just source code (and -sometimes- build instructions) distribution.