Redhat's code is Free software, actually. The page you link simply says they don't follow the free software distribution guidelines (and thus are not endorsed by the FSF/GNU project) because they also allow non-free software in their repos.

A better reference for Stallman's view here is probably https://www.gnu.org/philosophy/categories.html, which shows why Red Hat's business is probably reasonably described as a free software business (particularly since "the differences in extension of the category [open source] are small").

You're incorrect. Red Hat (and SUSE)'s distributions are free-as-in-freedom software (or at the very least, the majority of the distribution is free -- the link you posted is complaining about a very small minority of the software that is part of such distributions [which is a problem but is not as big of a problem as you claim]).

The fact that you won't get official updates after a trial period (or if your subscription runs out) isn't against the principles of free software. As a user, you still have the source code and have the freedom to maintain the distribution yourself (nobody does, but the freedom is still there).