I believe that it would stand to reason that if IBM/RH is not permitting redistribution of sources made available in their customer portal, this would constitute a violation of the GPL for any GPL package.
I would assume that IBM/RH will then need to take the Apple approach and quickly start working to replace GCC with LLVM and next rid itself of all GPL software and stick with MIT/BSD/OSC...
They do not restrict redistribution of what you already have access to, but they don't give access to future updates if you do redistribute. The GPL doesn't require them to give access to future updates either.
I would assume that IBM/RH will then need to take the Apple approach and quickly start working to replace GCC with LLVM and next rid itself of all GPL software and stick with MIT/BSD/OSC...