These mythical Indians, the thinking goes, were as inventive as the ancient Greeks or Romans. But they died out or disappeared before the Europeans arrived, so we aren't to blame for their loss. The only Indians we killed were the uncivilized, savage ones. While this was tragic, it wasn't that big of a loss to humanity. It's not as if we destroyed the Parthenon or the Coliseum, right?
For more on the subject, see Comic Books Featuring Indians.