We have already discovered two species that are very intelligent but technically less advanced than us — the common chimpanzee and pygmy chimpanzee. Has our response been to sit down and try to communicate with them? Of course not. Instead we shoot them, stuff them, dissect them, cut off their hands for trophies, put them on exhibit in cages, inject them with AIDS virus as a medical experiment, and destroy or take over their habitat.

That response was predictable, because human explorers who discovered technically less advanced humans also regularly responded by shooting them, decimating their populations with new diseases, and destroying or taking over their habitat. Any advanced extraterrestrials who discovered us would surely treat us in the same way. […]

Think again of those astronomers who beamed radio signals into space from Arecibo, describing Earth’s location and its inhabitants. In its suicidal folly that act rivalled the folly of the last Inca emperor, Atahualpa, who described to his gold-crazy Spanish captors thewealth of his capital and provided them with guides for the journey. If there really are any radio civilizations within listening distance of us, then for heaven’s sake let’s turn off our own transmitters and try to escape detection, or we are doomed.

Jared Diamond
Jared Diamond (b. 1937) American geographer, historian, ornithologist, author
The Third Chimpanzee, ch. 12 (1992)