On one side your Red Hat:
- takes non commercial open source and does integration and sells support. Also contributes to a megaton of open source projects across all layers of Linux.
The other you have the rebuilds:
- take Red Hat's commercial but open source work
- does no integration work whatsoever, since RHEL's already done that
- trivial contributions to almost no open source projects that aren't only necessary for their position as a clone
- undercuts RHEL in support offering since they don't have to do practically anything themselves.
So yeah, RHEL is an excellent citizen of open source and the others are just parasitic freeloaders.