But still, this being a video game it has no actual connectivity to the real world. It's kind of like people stereotyping themselves. Take the Pitt for example. Anyone could have said it was racist and laughs in face of people who died to fight slavery. The head of all the slavery operations is an African man (Asher, is his name right?). Anyone could say it was racist because it laughs in the face of people who died to fight slavery, making an African man the head of slavery to show the ironic-ness. But that's simply over anolyzing.
Same thing here. You're sort of stereotyping yourself saying your race is portrayed as the White-legs, Dead Horses and Sorrows. Unless there is something blatantly stating that all native and tribal races are to be portrayed by these characters, we can't assume they were. So for now, it's just your own stereotyping making you feel oppressed.
EDIT: I'd also like to point out that white, or 'non-colored' races can easily do what you're doing now. Saying Joshua Graham is a racist portrayal of their race. But people don't seem to connect racism to non-colored races for some reason. So, what I'm point out is just because you're colored or a race beside 'white' it doesn't mean only you can be discriminated against. People can be racist to blacks, asians, hispanics, etc. Whites are also in that mix, just so you know.