Stardust Memories

For those not familiar with NASA's Stardust Project, in 1999, a probe was launched to pass through the tail of a passing comet. It returned it's cargo, a canister comtaining dust collected in the comet's tail, to earth in January.

There is evidence of complex "organic" type molecules in the dust, which leads scientists to believe the possibility that comets crashing into a young earth may have planted the seeds of life here. So, are we all aliens? Even if this origin of terrestrial life is true, I don't follow this interpretation. If emigres can be considered citizens in their own lifetime, I suppose that 3.5 billion years of shared evolution should qualify us to call this planet home. Even if we were refugees originally.

Or should we just "go back where we came from"?