The limit of acceptable brutality and coercion shifts according to convenience for whoever is narrating, legitimizing, or executing that brutality/coercion. Ultimately, justifications and discourse don't really matter. As long as there is a profit motive, assembly lines which grind up life and shit out value will be built. They will run even if widely condemned and exposed in articles and books. The assembly line owners and managers will commit to reforms, apologize for travesties then continue to do them anyway, pay fines and pay off politicans, or relocate their operations.
In the dominant culture of where I write from, animals of the human species do not have inherent value. Most humans are used and discarded readily, especially if they do not have the material resources to escape punishments and controls. "Animals" as a class of object, as a type of renewable resource separated from "humanity" and beneath even the most abjectified human categories, are subject to practically limitless interference, manipulation and random cruelty from humans. Nearly all animals and their habitats are treated as expendable in service of human ambition. Animals who are protected by laws or widely beloved are still subject to total human control and killed if they become too inconvenient. The mass casualties of intensive industrial crop farming and resource extraction are considered completely inconsequential, with environmental assessments serving as box-checking rituals to give the appearance of due diligence. Certain types of animals are perpetually forced to breed in confinement just to be killed (e.g.: mass-produced chickens, cows, and pigs). Only the most dehumanized and animalized human populations are targeted with similar treatment: prisoners, drug-users, "crazy" people, people in the constructed regions of the "Global South" and "Middle East", etc.
Subjugation and exploitation of both "humans" and "animals" happen for the same reasons. Structures which make both things economically beneficial are all related. The global economy materially depends on the limitless use/abuse of animals because it is embedded and supportive of nearly all other power-hoarding, life-grinding industries and processes: pesticide production ♡ GMO monoculture ♡ animal agriculture ♡ devouring the rainforest ♡ fossil fuel and mineral extraction ♡ global transport networks ♡ imperialist and colonialist domination to enrich the imperial core ♡ police and prison industrial complexes ♡ manufactured xenophobia and racism ♡ structures of "citizenship" and migrant labour exploitation ♡ etc... All of these depend on one another and all would cease to function if animal autonomy and integrity of habitats were a non-negotiable condition for anything we did.
No one has an essential purpose of being the means to someone else's end. Animals are not here to be used for expansionist White supremacist humanist dreams.
I reject, any anarchist would reject, assholes exerting power to force others into roles in a made-up social order.