While I understand your statement, and agree with most of it, there is another reason for killing animals, and that is population control.
Some animals have no natural predators, and very rapidly overpopulate an area, which is much more detrimental to the animals than hunting/killing is.
Wild hogs are the most obvious "offender" in this category. They breed like rabbits, having two to three litters a year, sometimes 8-10 in a litter. While the little pigs are targets of prey for some predators, the hog herd is pretty intimidating toward any predator, so many of the babies grow up to make MORE babies.
All across the south, hogs have become an epidemic.... absolutely destroying farm and ranch land for use. It has gotten so bad that it has become legal to shoot them from helicopters. You wouldn't believe the damage a SMALL herd of hogs can do to farm crops or ranch land.... it literally looks like a huge roto-tiller has gone through.
Prarie dogs have been much the same way, but not quite as destructive..... but even they can destroy farm and ranch land quickly, if not controlled. They used to be controlled by poisoning, which tends to kill off a lot of other predator animals who eat the poisoned p-dogs. Plus, to my mind, a bullet that kills an animal instantly is MUCH preferred to a slow death by poison.
I have lost much of my desire to hunt, as I've gotten older, but I still would harvest a deer/elk/small pig simply because I enjoy eating them.