Certainly a fair question. The difference is that Red Hat always demanded that branding be stripped, and they didn't offer binaries to non-subscribers. You got source.

And projects like CentOS and Scientific Linux took that source and did the hard work of removing branding and building binary distributions on their own infrastructure.

Canonical, on the other hand, supplies binaries to all comers. And many a downstream project has used those binaries as a base.

Just like Ubuntu does with Debian.
I wonder if it's any different with Fedora. Is there a similar requirement for using Fedora packages in a downstream distribution?