Looking back, I want to believe that I was rejected because I was living abroad and they probably felt I wasn't really sure about moving to The U.S. They also need people who can legally work here as the referrals are their business model.
Well, I came here anyway on a sabbatical year. Been learning iOS programming, attending meet-ups and meeting awesome people. Just finished my first app and it's doing pretty well on the App Store.
I might apply again, trying to convey everything they look for in my application.