This clip from the movie Samsara makes a pretty clear case against factory-farmed meat, simply by showing how the animals are treated in life and death.
It’s graphic and upsetting, but it should be.
Chickens gathered by a combine and stuffed into tiny crates. Cows hooked up to rotating combination feeder/milkers. Lactating pigs held down in a supine position so litter after litter of piglets can feed on their swollen nipples.
This is not how food should be.