The GPL only cares about ensuring the four freedoms are maintained for binaries and their related sources.

No, the GPL goes beyond that. It not only ensures those four freedoms, but also ensures the freedom to exercise them without restriction. That's what the language in section 6 is meant to protect. If RH only limited potential access to future releases of binaries, I see that as fine and not a restriction. But RH is going well beyond that by terminating existing contracts; accounts; technical, web, and support access; and not refunding monies paid in advance for those services. (Theoretically, since they haven't done it to anyone yet that I'm aware of.) If legally those actions are not deemed a "restriction", then I'd agree with you.