Social Darwinism
A spectacularly ridiculous rendering of the noble savage, who is doomed to be crushed underfoot by the "march of civilization." (Civilization really does march in this one.) Lest the relentless social darwinisnist theme be lost on anyone, the film quotes Herbert Spencer directly.
The emphasis on the certain demise of the unfit Indian Race had commercial appeal; on the one hand, it absolved white audiences of guilt for the wrongs white settlers inflicted on Indians, on the other, it freed them to feel as much pity and regret as they desired.
While the film in its entirety may require more patience than most modern viewers possess, the quasi-documentary prologue is worth toughing out: it's so bad, it's good. (Still, it helps to throw back a few drinks first.)