Um...millions of OS X and iOS users are using Darwin as their main OS, as it is the foundation for those operating systems.
Foundation != the OS itself. Yes, OS X is built around a Darwin core, but it adds so much extra and *COMPLETELY NON-UNIXY* functionality on top of that, that it is, for the average user, a different operating system for all intensive porpoises. Same way that Android is based around Linux, yet most Android phone users never even see a hint of Linux in their day-to-day use of their phone. I doubt they'd even know what Linux was. Just like your standard Apple fan wouldn't know what Darwin was or why it was relevant.
Badges? We don't need no stinking badges.