Hi, that document is very old (last change was in 2012), and that was just a proposal.
We did in fact have those same hostnames as a proof of concept for a long while, but recently started to remove that in favor of a setup where we have everything in a single region S3 bucket but fronted by Cloudfront.
As a consequence, we have been removing all the older buckets.
Specific mirror URLs are never regarded as stable, as the only stable endpoint is the mirrorlist URL, and you are strongly suggested to use that rather than point to any specific mirror.
That should automatically find you the closest up-to-date mirror, and additionally gives you additional security protections against various forms of attacks: https://fedoramagazine.org/fedora-secures-package-delivery/.

I have added a warning to the top of the page to indicate this as well.