Because human beings have differences of opinions, no shit sherlock.
https://www.youtube.com/watch?v=mR-tbOxlhvE
So, I raised you Native Americans that ARE offended by it.
It's pointless to go "WELL WHAT ABOUT THESE GUYS?". We can probably google all day on finding someone with a difference of opinion. Besides, what some High School names itself in Arizona is a pretty far cry from the professional football team in our nations capitol, which is supposed to be politically correct,
because that is where national politics happen. Dan Snyder is embarassing the entire nation, and making the NFL look limp dick in comparison to the NBA who had no problem doing a senile old man over a private cell phone conversation.
Also, you cited Arizona as some kind of shining example of racial hegemony, which is absolutely ludicrous. That's the home of SB 1070. Nuff said.