What if Earth is like one of those un-contacted tribes in South America (the Amazon), and the whole Galaxy knows we're here but they've agreed not to contact us until we figure it out for ourselves.

Like say ufo's are real but it's just like when those tribes see planes flying by, they freak out and run around telling the whole tribe, they probably have wild stories about what they are and where they come from too.

Extraterrestrials see us like we see those tribes.

U must be a mind reader

Iain M. Banks referred to this as the "Outside Context Problem."

You're an island civilization that's lived on that island alone for thousands of years, and your tiny achievements seem like monumental history. You've sent out canoes a few days' sailing to see if there are other islands, but they found nothing, so the priesthood concluded the island is The World and your 15,000 people are humankind.

Then a boat 10 times taller than your tallest building crests the horizon, people in shiny metal armor hop on to your shores, and suddenly everything means nothing.

@nijabazaar, yeah, you could have a culturally complex society and still be technologically behind.