When you create your MOTOBLUR account on the phone, don't add any social networking accounts. Then remove the social networking widgets from the desktop (press and hold on any widget until a trash can appears at the bottom of the screen and drag it to the trash to remove it).
Voila, a non-social Backflip (the same is true of any MOTOBLUR phone). BTW, that's how you remove any widget from the desktop in Android, it's not specific to MOTOBLUR. And it doesn't delete the software from the device, it just removes it from the desktop and stops it from running automatically.