RHEL6 did use upstart, but when RH tried to submit patches/work with upstream like they do with most projects they ran into issues with Canonical's CLA and othe

RHEL6 did use upstart, but when RH tried to submit patches/work with upstream like they do with most projects they ran into issues with Canonical's CLA and other submission policies. So when Poettering came back with systemd they went "what the hell" and switched to that.