I once had a friend that would brag about killing his neighbor's cats that would wander around loose with anti freeze. He also came from a line of rednecks and it never occurred to him that anyone would find this practice to be objectionable.
He never complained to his neighbors about the cats or admitted to them that he knew anything about their deaths, but he thought that it was funny to watch them stagger and die an agonizing death.
I can empathize with the way that you feel.