https://www.theregister.com/2023/06/23/red_hat_centos_move/
I suspect if they are not acting in accordance with the law, Oracle's lawyers will let them know shortly.
Seems unlikely IBM have announced this to the world without checking the GPL first.
The RHEL approach seems to involve only supplying source code to customers already consuming binaries who will already be under other restrictions as they have agreeded to other T&C's.
RHEL has been moving towards this for a decade, it seems unlikely they have forgotten about the GPL.
https://www.theregister.com/2023/06/23/red_hat_centos_move/
The Register seems to think they are acting perfectly in line with the GPL.