The plumbing layer as the new kernel

To my knowledge, that's one or two developers, who, for a time happened to be employed by RedHat. At least one of them was very likely fired because of this attitude. I think it's rather unfair to extrapolate from that into assuming that RedHat projects in general are hostile to third party contributions. From what I can tell, Gnome doesn't seem to be. Or LibreOffice, systemd, PulseAudio or JBoss.