Why exactly do YOU need and use history?

"Those who cannot remember the past are condemned to repeat it".-George Santayana

Throughout history politicians, world leaders, and tyrants have committed acts of extreme brutality and abused their position of power, have lied to the public to justify totalitarian and draconian laws, unjustified wars, apathy to poverty and suffering, slavery and cruelty to their fellow man, and, what is most important is that they have used the same excuses to justify themselves

Would society disapprove of racism and fascism so strongly had future generations not been taught about the crimes of Hitler and Mussolini? Would the war in Iraq have been opposed so strongly had people not been aware of the war in Vietnam, and the excuses used by governments and the lies that were told to justify the war? Would draconian surveillance and privacy invading laws be opposed if no-one had read the works of George Orwell? Would freedom of speech be protected and regarded as such an important value if people were not taght about the US Constitution and the bill of rights?