It's perfectly possible for Facebook to not track users at the moment and simultaneously prepare for a future where this is not only acceptable, it's expected. Facebook has placed a long-term bet that people will willingly share pretty much everything they do. When they file patents like this, they're skating where the puck is headed, not where it is now.
Let's be real. Facebook has not "placed a long-term bet"; they are actively engineering that reality right now, despite loud and frequent objections from users.