The Europeans left africa when asked to do. Most of them did at least. Obtaining Land through the battlefield, which is how much of the land in the New World and Oceania was obtained, is pretty much fair and square I'd say. You lose a war; you lose your land. That's been the unwritten rule for all of human history. THe Arabs wanted all-out-war with the Israelis. The Israelis won. The Israelis got to take the land that's just how it goes.