Carrying =/= getting kills.

A carry is not the one who manage to finish of enemies. A carry is the one who manage to mage plays, or counter the plays that the enemie makes. A carry is the one who deals a lot of dmg and manage to stay safe. A carry is the one who is making the decisions.

So yeah, just because you are 12/2 with doesnt mean you are carrying, it means you manage to make the killing blow on 12 people. You wanna know how I know you are not carrying? The fact that you start feeding and go 12/6 at the end of the game and we still manage to win.