History America has multiple roots. Her founders were educated, well traveled, experienced people. Recently, the 500th anniversary of Columbus's landing renewed the debate about his legacy. Although he contributed little to America's intellectual heritage, his voyage made its founding possible. It's absurd to apply our modern standards of behavior to him.
Opinions come and go, and popular impressions change.
Actually, both-and neither. Look at the portrayal of native Americans by Hollywood. Later, movies like Dances with Wolves admitted to both good and cruel soldiers, as well as Indians. It's a vast and often controversial subject. Just look at the Kennedy assassination, which is still within living memory.