Start with God.
‘And [Peter] saw heaven opened, and a certain vessel descending unto him, as it had been a great sheet knit at the four corners, and let down to the earth: wherein were all manner of four-footed beasts of the earth, and wild beasts, and creeping things, and fowls of the air. And there came a voice to him, Rise, Peter; kill, and eat.’ (Acts 10: 11–13.)
The Bible is a meat-eater’s manifesto. Before the Fall, Adam and Eve were vegetarian. They fed on grains, nuts and fruits. Then Eve ate the fruit of the tree of knowledge of good and evil—or at least that’s the way Adam explained it to God. They were cast forth from the Garden, plunging mankind into original sin from which redemption can come only through the grace of Christ, whose flesh is eaten periodically in the form of the Eucharist. Hardly were Adam and Eve out of Eden before God was offering ‘respect’ to the flesh sacrifice of Abel
Ringing in Man’s ears was the Almighty’s edict, as reported in Genesis 1:26–28: ‘Let us make Man in our image, after our likeness: and let them have dominio. . .over all the earth, and over every creeping thing that creepeth upon the earth. . .Be fruitful and multiply, and replenish the earth and subdue it.’ Thus did the biblical God launch humans on the exploitation of the rest of the natural world, theirs for the using.footnote2
Dominion over ‘Un-Christian’ nature was at the heart of it, as C.S. Lewis spelled out frankly enough: ‘Atheists naturally regard. . .the taming of an animal by man as a purely arbitrary interference of one species with another. The “real” or “natural” animal is to them the wild one, and the tame animal is an artificial or unnatural thing. But a Christian must not think so. Man was appointed by God to have dominion over the beasts, and. . .the tame animal is therefore, in the deepest sense, the only “natural” animal—the only one we see occupying the place it was made to occupy.’footnote3