what kind of psychopath wants to kill an animal themselves?

The mental health issues among abattoir workers is way above the national average. It takes a toll.

I don’t know, what kind of a psychopath pays an industry to do it for them

Out of sight, out of mind. We have professional wet workers for a reason. If everyone had to do this shit themselves, much of it wouldn’t get done. Hell, I still stay up at night thinking about my elderly dog being put to sleep in front of me at the vet’s. If I’d had to push that syringe down myself, I’d have probably sawed my own hand off by now, purely out of shame.