In humans, we don’t usually castrate them because it throws their hormones out of whack, and causes all kinds of issues, but wouldn’t that also be the case for some animals, since their hormones systems are fairly similar?
Why is it that that we remove the testicles entirely, rather than giving them vasectomies like we do for humans?
For a cat that you are personally paying to have neutered, they will do anything you want. There are options to just surgically sterilize and leave everything intact. But that’s not only much more expensive, it also leaves their behavior the same which isn’t always desirable. Unless you enjoy a male spraying all over your house, that is.
But for a farmer that has to sterilize a herd, they aren’t spending the time and money on a vet to come and surgically neuter every animal they have. A rubber band is cheap and can be done by the farmer, and a vet only has to be called if an infection happens. It’s been done for centuries. No one is going to spend 50 times the amount of money if they don’t have to.