Microsoft sold somewhere in the neighborhood of six million copies of Halo 2. With two people using each copy of the game (dad/son, brother/brother, brother/friend, I won't pretend to figure girls into this equation. Girls dont' add up in real life) that means there's 12 million people who have played Halo. Add to that all of the uncountable used copies that have sold and you could easily come away with a game that 20 million people have played.
That means there should be 20 million crazed snipers. Or 10 million. 2 million? One million? Ten thousand? ONE thousand?
There was ONE sniper.
You take twenty million of ANYBODY and you'll find at least one of anything. One cake decorator? One lawyer? One person who can pop an eyeball out? A rapist? A Senator? A nun? Because these people all play Halo, does that mean Halo made them all what they are?