If you provide GPL software to your customers, you have to provide everything they need to build this exact version yourself, not point them at a repo and tell them to figure it out.
Red Hat does provide all of that to RHEL customers. This is a discussion about what non-RHEL customers get.
Even non-customers are provided with all of the sources they they could use to build RHEL, given some additional effort. It's less trivial than it used to be, but not particularly difficult.
Alma takes the approach of reconstructing RHEL using these public sources, Rocky takes the approach of buying AWS VMs running RHEL for a few minutes at a time so that they can download RHEL sources as a "customer" while only paying a few dollars a month to do so.
The point is, even non-customers can rebuild RHEL using sources made publicly available by Red Hat if they so desire. It's not "effectively closed source", even to them.
