Answer:
Because History was writeen by the European point of view, and just recently we're trying to rethink this History. However, because of the tradition, it's hard to replace Columbus, or any other European conquistador.
Step-by-step explanation:
The Native American's point of view, and other groups around the world, we are just recently understanding their point of view about the story. European tradition dominated History studies for centuries, and even with discoveries, it's pretty hard to replace this History. This will take time.