The GPL essentially states that you must give copies of source code to the same people you give copies of binaries. Red Hat is not under any strict requirement to give copies of source code to everyone. What this means in practice is that Red Hat is essentially forcing everyone to agree to their license terms, in addition to the GPL, in order to access the RHEL source code.

What Red Hat appears to be doing is very much in a gray area, and at the very least it violates the spirit of the GPL if not the actual agreement as written. In fact what they’re trying to do may very well end up contravening the GPL. This is one of the clauses in the GPL:

If the Program as you received it, or any part of it, contains a notice stating that it is governed by this License along with a term that is a further restriction, you may remove that term.

In other words, if Red Hat tries to wrap the GPL in some bullshit extra license that says e.g. “you are not allowed to give copies of this source code to a third party” (such as, say, Rocky Linux or AlmaLinux or some other downstream distro), then I think their customers can simply remove that term from their license as it’s a “further restriction” as defined by the GPL. However, Red Hat also has in their license some restrictions that allow them to terminate their agreements with a customer at any time and for any reason whatsoever. Red Hat wields that like a cudgel, threatening their customers with Red Hat license termination if those customers choose to exercise their full rights under the GPL in ways that Red Hat doesn’t like. This article has a much more in-depth analysis if you want to know more.