Red Hat isn't changing the terms of the GPL. What they're doing is making access to the GPL code a benefit of maintaining an active Red Hat subscription, which

Red Hat isn't changing the terms of the GPL. What they're doing is making access to the GPL code a benefit of maintaining an active Red Hat subscription, which has its own terms and conditions. If you have an active Red Hat subscription, then you can look at the source code all day long and may be able to redistribute it for purposes of bug fixes, etc. What you can't do is use your subscription to obtain the source code, which you then redistribute to someone that doesn't have a RH subscription. This would violate the terms and conditions of the RH subscription. Basically, they've inserted a new licensing layer 'above' the GPL: you can't obtain the GPL code unless you agree to the terms of the RH subscription in the first place. In other words, the RH subscription Ts and Cs supersede the GPL.