It's not really a celebration of their culture, it's nothing more than a tough looking guy in a head-dress and some face paint. Who does he represent? What does he really tell you about Native American culture?
Why does it need to tell anyone anything about Native American culture? People have Pacific Island tribal tattoos, that tell you nothing about Samoan culture or Tongan history. The Chiefs emblem is simply a picture, and it shows no disrespect. For the fams, and most rugby fans, it represents Exeter Chiefs.
Next time you buy a pizza, will you make sure there's a history of Italy included. Or if you buy a Peugeot, sign up for a course on French culture?