The message is to reverse the role between livestock and humans.
Humans become food, source of milk, while livestock consume the humans.
However, the humans disguised in livestock masks are still humans which make them "just" cannibals.
Really disturbing, especially when the cannibals pray to Jesus disguised by an animal mask.
Am I sinful to eat cow, chicken or pig meat? Do cattle suffer as much as the human victims in the movie? maybe... If the movie's objective is to encourage viewers to become vegetarian, it may be working on me.