"A Facebook spokesperson said the disabled version of the app acts like it's been deleted, so it doesn't continue collecting data or sending information back to Facebook. But there's rarely communication with the consumer about the process." If this is the case then why not allow it to be deleted?
Baking certain apps into the system partition is typically how vendors ship an out of the box experience, since apps are generally downloaded via the Play store, which requires the end user to first log in with Google. In that case, the only way to delete apps is to 'root' the phone, which generally isn't enabled and not something Facebook has control over.
iPhones come baked in with a number of apps but you're able to delete the ones you don't want to use.