I think it's rather sad how the natives were apparently beaten badly enough that you can get away with mocking them. Here's a simple mental exercise; how would you feel about a team being called the Washington Niggers, Spics, or Chinks? If those are not acceptable (and I pray you say they are not), why is the Washington Red Skins?
Just imagine the logo, too. The profile of a stereotypical looking black dude, or Mexican bandito, or a Chinese mandarin.