https://sfconservancy.org/blog/2023/jun/23/rhel-gpl-analysis...
I think RedHat's theory is that the GPL doesn't entitle you to updates or support, so restricting them can't be considered an additional GPL restriction.
You could say that without the updates, RHEL is not fit for purpose, and therefore you should be entitled to them. Sounds like a complicated legal argument to have though.
I agree that RedHat are certainly not ethical actors in the FOSS community though.