I kinda think the opposite is true. It's people who live in cities who join PETA. Country folk get acclimatized to commoditizing animals.

I'd like to see a summary of the evidence that many Native Americans actually prayed for forgiveness to animal spirits. There's been a lot of retrospective "reframing" of Native American culture in the past 100 years--go to a pow-wow today and an earnest Native American elder may tell you stories about their great respect for the Earth, but I don't find these stories in 17th thru 19th-century accounts. Praying for forgiveness makes a great story, but you usually hear about it from somebody like James Fenimore Cooper rather than in an ethnographic account. Do contemporary accounts from the Amazon say that tribespeople there do that?

(Regarding the reliability of contemporary Native American accounts: Once I was researching the Cree Indians, and I read an account, circa 1900, by a Cree, boasting that their written language was their own invention and went back generations before the white man came. The next thing I read was an account from around 1860 of a white missionary who had recently learned Cree and invented the written script for it. I may possibly be confusing the Cree with Ojibway, but it was the same language in both stories.)

I'm not aware of any Western religion that says cruelty to animals is a sin. Individual interpretations, maybe, but I'm pretty sure you won't find a word about it in the whole of the Bible. The Anglican church was fine with bear-baiting. I don't think the Catholic church complained about vivisection.

And it's certainly true that tribal cultures gave zero or negative weight to the well-being of competing tribes. Utilitarianism is tricky to apply when you have to periodically kill your neighbors to survive.

In any case, indigenous cultures aren't the ones complaining that utilitarianism leads to utility monsters. The people who've made those arguments do have their own preferred utility monsters.