By this logic, how could anyone “discover” a lost tribe or unknown civilization?
Columbus had courage, something that liberals do not like and do not understand.
Columbus clearly discovered America in the sense that almost no maps or atlases or catalogs on the world island comprising Europe, Asia and Africa had any hint of the existence of land between Asia and Europe in 1492 but by 1510, almost all new maps and atlases reflect the knowledge of America.
“Viking Maps” and sagas, to the extent they actually existed are at best ephemera, not part of mankind’s base of knowledge. That information had almost no influence on the wider world’s perception, unlike Columbus.