"Psychopath" is a bit much.
We come from hundreds of thousands of years of hunters. It would be odd if members of our species didn't get as much inborn satisfaction from successfully hunting down meat as any other predator.
As for trophies on the wall, taxidermy is a quite recent invention (late 1800s). Other than preserving skins for clothing, that is.
Yet, many of our ancestors (from almost any culture in the world) would wear claws, teeth, horns, bones, skulls, or other symbols of their success at hunting. Or paint their prowess on cave walls.
I'm sure if they had a practical way of preserving a head on the wall, they would have cheerfully done it.