I don't understand the logic here. It's okay to kill animals as long as they've spent their entire lives in human-inflicted suffering? For the record, I eat me

I don't understand the logic here. It's okay to kill animals as long as they've spent their entire lives in human-inflicted suffering? For the record, I eat meat, and I have few qualms about eating caged animals, but arguing it as more humane is beyond perplexing to me.