My initial thought was, "Stupid politically correct people can go die of explorer-borne diseases in a fire", but then as I read about people mentioning Neil Armstrong and Lewis & Clark and others, I'm warming to the idea. I think the American persona, at least how we like to see ourselves, is as the leading edge, as explorers, whether it be physical exploration or science or culture or any other topic. Columbus fits that mold, but so do a lot of other worthy explorers.
I think I like the whole Explorers Day concept.
Eliminate the racist "Chiefs" nickname and become the Kansas City Ermines. It's time, people.