How so? If that were true, we'd see factory farms lobbying for stronger laws against animal cruelty, to prevent competitors that do not care about animals from forcing everyone into the current state of things.
Truth is, a lot of people - inside and outside - just don't care. Ceteris paribus, they'd prefer animals to have happy lives, but that preference is outweighed by needs of convenience, profit, human healthcare, and food security.
Psychopaths are rare. But, with apologies to Burke/Mill[0], the only thing necessary for the triumph of evil is to separate good men from it by enough layers of abstraction.
--
[0] - Apparently [1], the Burke never said that, and the original sounds closer to "Bad men need nothing more to compass their ends, than that good men should look on and do nothing", which is incidentally even closer to my paraphrase.
[1] - https://www.independent.co.uk/voices/the-top-10-misattribute...