It doesn't matter how many game genres I expose my son to - RPGs, puzzle, space, adventure, sports, visual novel... No matter what, he goes back to blowing zomb

It doesn't matter how many game genres I expose my son to - RPGs, puzzle, space, adventure, sports, visual novel... No matter what, he goes back to blowing zombies away in Call of Duty Multiplayer. He could do that for 12 hours a day if I let him. Interestingly, he otherwise enjoys intellectual and artistic pursuits, but I feel there is some deep instinct showing its face in his game preferences.