Most people in time and space have considered it strange to take the well-being of non-humans into account

I think this is wrong in an interesting way: it's an Industrial Age blind spot. Only people who've never hunted or herded and buy their meat wrapped in plastic have never thought about animal welfare. Many indigenous hunting cultures ask forgiveness when taking food animals. Countless cultures have taboos about killing certain animals. Many animal species' names translate to "people of the __." As far as I can tell, all major religions consider wanton cruelty to animals a sin, and have for thousands of years, though obviously, people dispute the definition of cruelty.