The closest thing you're able to do is disable other people being able to see your stats, but you can't actually turn off the stat tracking because that'd make it hard for it to judge the points other people get/lose when they kill/get killed by you. Because it's based on the difference between scores, if you turn off the ability to have a score, how does it weight kills and deaths? There'd be no real fair way to do it, and it'd also easily enable people to stack the stats by killing a "dead person" over and over again.