Based on this reasoning, there are many nicknames besides Indian nicknames which are offensive.
Boston Celtics is offensive to the Celtic people.
Notre Dame Fighting Irish is offensive to the Irish.
San Diego Padres is offensive to priests and clergy.
New Orleans Saints and Los Angeles Angels are offensive to religion and religious people.
Minnesota Vikings is offensive to Scandanavians.
Pittsburgh Pirates is offensive to real pirates.
Pittsburgh Steelers is offensive to real steel workers.
Milwaukee Brewers is offensive to real brewery workers.
Green Bay Packers is offensive to real meat packers.
Texas Rangers is offensive to the law enforcement agency.
Buffalo Bills is offensive to the memory of Buffalo Bill Cody.
Dallas Cowboys is offensive to real cowboys.
And all of the animal nicknames are offensive to the animals. The PETA crowd can get involved with all of those and express mock outrage.
What about the Cleveland Browns? Is that racist? Is the San Francisco or New York Giants insensitive toward little people? What about the Jersey Devils? Offensive to Christians?
Does Saints and Angels offend atheists? Where does this pc nonsense end?