Modern Warfare 2 player claims to have reached 10th prestige without getting a single kill
One of the nice things about the long-running Call of Duty franchise is that it brings in a wide variety of different players and playstyles from across the spectrum of gamers.
There are sweaty grinders who want to rank up the competitive ladder, there are casual players who enjoy turning off their brains and shooting everything on Shipment 24/7, and everything in between. This also includes players who never shoot their gun or even get a kill, apparently.