The problem isn't having a name that refers to some group of people, it's using offensive slurs and images and disregarding the people whom your name and image represent. I don't think there's a problem if you maybe use the tribe's name, a respectful, relevant image, and you actually, ya know, talk to the tribe whose representation you're using. The problem is when you use whatever name and image you want, regardless of what it actually means. They use references to entire people as if they're just objects for them to use, like "redskins" is comparable to the "knicks" and nobody should have a problem with it, it's just a name, just a thing, it doesn't mean anything because we say it doesn't, regardless of where it came from.