Why did Stellar decide on using Facebook accounts to enforce the one account per person rule, instead of something better like mobile numbers? There are more people with cell phones than there are with Facebook accounts. Acquiring large batches of phone numbers to game the system is harder since it costs money and is more easily detectable.
Even if this guy isn't gaming the system with fake Facebook accounts, I'm sure others already are.
Indirectly they are requiring mobile numbers because they require a verified Facebook account which means giving your phone number to Facebook for verification (at least for me, could be different for other countries).
Even if this guy isn't gaming the system with fake Facebook accounts, I'm sure others already are.