Maybe they're are just young people who really believe in Bitcoin.
I considered that...but hashing faster doesn't increase or foster bitcoin adoption -- in fact I'd wager it consolidates the mining instead of distributing it...with $1500-$30000 needed to even make it worthwhile in power, everyone but the big guys are shut out. Bitcoins are generated at the same rate regardless of the network hash rate. So the only benefit to a faster hasher is when you're the only one with it and it's a monetary benefit.
And maybe they need customers money in order to fund development.
Possibly...still just seems too good to be true without some sort of catch-22 somewhere.