Not necessarily. A community is more than than the amount of players on at any one time, too.
It's sorta like going to the mall one day, doing a headcount, then proclaiming that that's the entire population of the town.
The Facebook event attracted 600 people. Some people don't play anymore, and wanted to claim the hat anyway. Other people don't have Facebook or didn't want to join.
What have we learnt today?
The population count on RMS is silly. And so is basing a population off of any one moment only.