Are they seriously claiming they contribute to every one of the tens of thousands of packages they include in their repo? I'd like to see some proof of that.
If they're taking any open source app, and just including it in their repo without at least 1 RH patch.. then they are "simply tak[ing] upstream packages and rebuild[ing] them".
RedHat absolutely makes money from upstream OSS contributors, and not all of those projects get money or patches from RedHat.