I received a message saying I had to forward it to 15 people, or
my account will be disabled within 2 weeks, Apparently, this is to
purge facebook of those not using it enough, Is this true?

Here is the message I received:

Dear Facebook Members, Facebook is recently becoming very overpopulated. There have been many members complaining that Facebook is becoming very slow. Records show that the reason is that there are many active Facebook members and, on the other side, many new Facebook members. We will be sending this message around to see if members are ,  active or not. If you are active please send to at least 15 other users using Copy + Paste to show that you are still active. *Those who do not send this message within 2 weeks will be deleted without hesitation to create more space.*Send this message to all your friends and to show me that your still active and you will not be deleted.Founder of Facebook,Mark Zuckerberg