Columbus may have re-discovered American "Islands" for Europe, after some other Europeans did, apparently there's big evidence that Leif Erikson discovered America first, as well as some other legends which may or may not be true, then Rosslyn Chapel seems to suggest earlier American exploration, or possible Richard Amerike, or Jan of Kolno, seem to also be potential possibilities.
The bottom-line is Columbus had little to do with the brutality of later Colonists.
The bottom line is the Left hates Western Culture and wants to destroy or marginalize it.