You don't own a housecat and have never lived with one, have you. Housecats are having a great time stalking and killing everything from insects to lizards to rodents to birds. My cats are well-fed, but that doesn't stop them from massacring any small critter in my yard. Those critters are in no way endangering my cats, yet my cats slaughter them with joy. I watched my neutered male cat bat around a dead snake for 5 minutes. He kept throwing it so it looked alive, and then pounced on it again. Housecats are domestic serial killers. Dogs aren't much different. Had a bird stuck in my screen room. My well-fed boxer reveled in killing the mockingbird that got in. It's part of nature. We (and most other creatures) enjoy most of what we have to do to survive. That's why eating and sex are so much fun. It's part of survival. Hunting is just the same way.