Honestly I have always found Brando to be really not very entertaining, and a self important narcissistic arrogant pompous jerk.
It's funny he should say that about Native Americans considering his whole Oscar fiasco. And it should be noted that whenever John Wayne had a say so in how to portray Native Americans, he generally showed them in a favorable light.
Anyway as I recall, John Wayne only rarely went up against Indians in his own movies, it seems to me that Pappy is the one who should been the target of their wrath.