I read that the government enforced the racial rules, not the natives, but the natives went along with it because it was that or a long battle for the benefit of a minority of white members, so they made the NAC for natives only... I think you need 1/4 native blood minimum. Fair enough, they've had so many problems with white culture that one can understand them leaving whitey to fight for himself (and this is exactly why the Peyote Way Church of God was formed- when the white founders left the NAC in the wake of the racial legislation).
I am told by my Haudenesawnee friend that some reservations are not welcoming to white people and some can be racist against whites. Again, I do not find this surprising in the least, because the reservation schools are still haunting the memories of the living, but still, racism is always a sad thing. Although maybe she was just telling me that because she didn't want me to meet her family! Her mother always told her that life will be a lot easier for her if she marrys a native boy.