Unfortunately, it’s the name that inspired this school to use these chants, wear the headdresses, etc. The name does matter, because it provides the context for which the behavior occurs.
My school’s mascot is the Knights. And because of that, we have all of these traditions and ways of existing that surround that identity. Our marching band uniform has that look. We have chants inspired by our mascot. Even the warning bell in our school is a medieval trumpet call.
So yes, the name standing alone might not offend you, but that name inspires all of the things that are offensive. Just like the word “fire”. Alone it means nothing to anyone. But if I shout it loudly in a hospital and cause panic and pandemonium, whether or not there is an actual fire or not, that word now has meaning attached to it and led to a behavior. The school has done the same with “Indian”. It has completely become a part of the school culture and inspired all of these things that are not okay.
Words matter and have weight to them. They influence how we behave and what we think.