The history of deliberate cruelty to other species has taken a strange course. The early hunter had a kinship with animals. He respected them. So did the early farming people.
I would like to ask native speakers of English why YOU think the author made huter singular not plural but people plural, instead of the early farmer not singular and its effects, I mean, the impression you get. I would like to know that. I know hunter, animals and people are generic. I think animals shows all the species generally. People is people generally. So why only hunter is singular?
Well, it could be that the author didn't give the lack of parallel between "hunter" (singular) and "farming people" (plural) much thought when he/she crafted the sentence.
Or it could be that, after using the single "hunter" as a rhetorical device [I think this is a synecdoche but I'm not quite sure, somebody help] the author decided to return to a more straightforward style.