Sure the GPL does require distributing source and allowing others to distribute that source, but Red Hat isn't obligated to do business with everyone, so Red Hat doesn't have to sell a subscription to Rocky. And if some other subscriber published sources, Red Hat doesn't have to renew the contract with them so they could be cut off after a year. There's no way you could have a usable stable distro that way.

That said Red Hat is not planning to do that. The point is just that you should be grateful to Red Hat. They're going above and beyond what they have to do, and these RHEL rebuilds are only possible because Red Hat makes it possible. Red Hat still does it even though people like Oracle take it and package it up as a direct competitor (a pretty nasty thing to do in my opinion).

Also, not all of RHEL is GPL licensed, so significant, important pieces aren't required to be released anyway ...