We didn't start by spreading the things we learned off to the other people left behind on earth. The first things we did was to improve our technology, and communication systems, we can't afford any sort of errors as Colby said. What came next was the testing stage, for which we needed people to help us from different parts of the world. So we needed to reveal some information. We obviously can't tell them everything, it's not possible to explain everything without the other people raising dumb questions and assumptions.
So the question came, how must we reveal the basic idea of what's happening to reel them all in, while we don't have to explain details that are difficult to explain and make them understand?